Electronic endoscope

ABSTRACT

An electronic endoscope includes an outer shell that is formed in a tube shape and whose peripheral wall is provided with a transparent window part extending in an axial direction, a solid-state imaging device that is provided inside the outer shell, an objective optical system that includes an objective lens for focusing object light through the window part and that forms an image onto the solid-state imaging device, and a drive mechanism that causes the objective lens in the objective optical system to move along an axis of the outer shell. The drive mechanism includes a lens holder for supporting the objective lens, a feed screw extending along the axis of the outer shell, and a motor for driving and revolving the lens holder about the feed screw as an axis of revolution. The lens holder engages with a thread groove of the feed screw.

The present application is a Continuation application of U.S. patentapplication Ser. No. 12/999,815, having a §371(c) date of Dec. 17, 2010,which was based on PCT/JP2009/060885 filed on Jun. 15, 2009, which isbased on and claims priority from Japanese patent application Nos.2008-157991, 2008-157992, 2008-157993, 2008-157999, 2008-158000,2008-158002, 2008-158004, 2008-158005, 2008-158006, and 2008-158013filed on Jun. 17, 2008, the entire contents of which is incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to an electronic endoscope.

BACKGROUND ART

In an electronic endoscope described in Patent Document 1, an insertpart of a small diameter is inserted into a hole or an abdominal cavityso that an objective lens attached at the tip of the insert part isdirected to a diseased part or the like in the direction of insertion.Then, in this state, image information is acquired.

Further, in an electronic endoscope described in Patent Document 2, anobjective lens is provided in a side surface of the tip part of aninsert part. Thus, an image is acquired within the field of viewextending sideward.

Further, in an electronic endoscope described in Patent Document 3, anomnidirectional light receiving unit is provided at the tip of an insertpart so that an image covering the entire circumferential directions atthe tip of the insert part is acquired using reflection by a convexmirror provided inside the omnidirectional light receiving unit.

Further, an electronic endoscope described in Patent Document 4 is ofcapsule type used for medical checkup of the alimentary canal in themedical field. This electronic endoscope has an imaging device in theinside, and hence continuously performs image pick-up of the inside ofthe alimentary canal in the course that the electronic endoscope isconveyed along the inside of the alimentary canal in association withperistaltic motion of the alimentary canal.

In many cases, the imaging device accommodated in the tip part of suchan electronic endoscope has a smaller area and a smaller number ofpixels than a solid-state imaging device used in a digital camera or thelike. Thus, when a detailed image of a diseased part or the like isacquired, the image information obtained by each single image pick-up islimited to the image of a small view field region.

Thus, when detailed image information is to be acquired over a largeregion, the operator of the electronic endoscope need repeat imagepick-up multiple times with adjusting the insertion position of theelectronic endoscope by manual operation. Thus, attention need be paidto both of the operation of searching a diseased part or the like, thatis, adjusting the insertion position, and the operation of image taking.Thus, skill has been necessary in such work.

Further, in the electronic endoscope in which an image over the entirecircumference of the tip of the insert part is acquired using anomnidirectional light receiving unit, image information over the entirecircumference region of the insertion position where image pick-up isperformed is obtained at once. Nevertheless, the image pick-up region isrestricted to a region of a narrow width at the insertion position.Thus, in order that entire circumferential image information should beacquired over a large region, image pick-up need be repeated in such amanner that the insertion position is adjusted at each time. This causesa possibility that information is missing at a junction part of imagesor that useless image pick-up is repeated.

Further, the electronic endoscope of capsule type is conveyed along theinside of an alimentary canal by peristaltic motion of the alimentarycanal. Thus, the operation of moving the field of view is unnecessary.Nevertheless, such an electronic endoscope is not applicable to a holeor an abdominal cavity where peristaltic motion is absent.

CITATION LIST Patent Literatures

-   Patent Document 1: Japanese Laid-Open Patent Publication No.    H09-192084-   Patent Document 2: Japanese Laid-Open Patent Publication No.    H03-191944-   Patent Document 3: Japanese Laid-Open Patent Publication No.    2003-279862-   Patent Document 4: Japanese Laid-Open Patent Publication No.    H09-327447

SUMMARY OF INVENTION Technical Problem

An object of the present invention is to provide an electronic endoscopethat has a new structure for realizing easy and accurate acquisition ofdetailed image information over a large region.

Solution to Problem

(1) An electronic endoscope characterized in that an outer shell that isformed in a tube shape and whose peripheral wall is provided with atransparent window part extending in an axial direction; a solid-stateimaging device that is provided inside the outer shell; an objectiveoptical system that includes an objective lens for focusing object lightthrough the window part and that forms an image onto the solid-stateimaging device; and a drive mechanism that causes at least the objectivelens in the objective optical system to move along an axis of the outershell.

(2) An electronic endoscope that is inserted into a subject and thenacquires an image inside the subject, characterized in that: a lensholder that has a tube-shaped part; a wide-angle lens that is mounted onthe lens holder and that is arranged on one-end side of the tube-shapedpart in a state that an optical axis is aligned to a center axis of thetube-shaped part so that an observational field of view extends to asideward region of the tube-shaped part; an imaging device that receiveslight acquired through the wide-angle lens and that converts the lightinto an electric signal; a transparent cover that covers one-end side ofthe tube-shaped part and at least whose part facing the observationalfield of view of the wide-angle lens has transparency; a tube-shapedbody part that is connected to the transparent cover on the-other-endside of the tube-shaped part; and a driving section that is arrangedinside the body part and that causes the lens holder to advance orretreat in the center axis direction.

(3) An electronic endoscope characterized in that: a cylindricaltransparent cover at least whose observation window in a cylindricalpart is transparent; a body part that has a cylindrical part providedcontinuously to the cylindrical part of the transparent cover; a lensholder that revolves about a center axis of the transparent cover in aninside of the transparent cover and the body part and that moves in adirection of the center axis; an objective mirror that is provided inthe lens holder and that reflects, toward the body part, light enteringthrough an objective lens provided at a position facing the cylindricalpart of the transparent cover, an imaging device that receives lightreflected from the objective mirror and that converts the light into anelectric signal; and a driving section that is provided inside the bodypart and that drives and revolves the lens holder so as to drive thelens holder in the center axis direction.

Advantageous Effects of Invention

According to the present invention, detailed image information over alarge region is acquired easily and accurately.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external appearance perspective view of an example of anelectronic endoscope used for describing an embodiment of the presentinvention.

FIG. 2 is a longitudinal sectional view of an electronic endoscope shownin FIG. 1.

FIG. 3 is an exploded perspective view of an electronic endoscope shownin FIG. 1.

FIG. 4 is an enlarged perspective view of an image pick-up drive unitpart that contains a solid-state imaging device in an electronicendoscope shown in FIG. 1.

FIG. 5A is a perspective view used for describing operation of a lensholder for holding an objective lens in an electronic endoscope shown inFIG. 1.

FIG. 5B is a perspective view used for describing operation of a lensholder for holding an objective lens in an electronic endoscope shown inFIG. 1.

FIG. 6A is a perspective view used for describing a driving section formoving a lens holder for holding an objective lens in an electronicendoscope shown in FIG. 1.

FIG. 6B is a perspective view used for describing a driving section formoving a lens holder for holding an objective lens in an electronicendoscope shown in FIG. 1.

FIG. 7 is a partly sectional perspective view of a driving section shownin FIG. 6A.

FIG. 8 is a functional block diagram showing an electronic endoscopeshown in FIG. 1.

FIG. 9 is a control flow chart of an electronic endoscope shown in FIG.1.

FIG. 10 is a schematic diagram showing an image map generated by anelectronic endoscope shown in FIG. 1.

FIG. 11 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 12 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 10.

FIG. 13 is an exploded perspective view of an electronic endoscope shownin FIG. 10.

FIG. 14 is a sectional view used for describing a view field region inan electronic endoscope shown in FIG. 10.

FIG. 15 is a schematic diagram showing an image map generated by anelectronic endoscope shown in FIG. 10.

FIG. 16 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 17 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 16.

FIG. 18 is an exploded perspective view of an electronic endoscope shownin FIG. 16.

FIG. 19 is a perspective view used for describing a driving section formoving a lens holder for holding an objective lens in an electronicendoscope shown in FIG. 16.

FIG. 20 is a longitudinal sectional view used for describing operationof a lens holder for holding an objective lens in an electronicendoscope shown in FIG. 16.

FIG. 21 is a longitudinal sectional view used for describing operationof a lens holder for holding an objective lens in an electronicendoscope shown in FIG. 16.

FIG. 22 is a schematic diagram used for describing a view field regionin an electronic endoscope shown in FIG. 16.

FIG. 23 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 24 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 23.

FIG. 25 is an exploded perspective view of an electronic endoscope shownin FIG. 23.

FIG. 26 is a longitudinal sectional view used for describing operationof a lens holder for holding an objective lens in an electronicendoscope shown in FIG. 23.

FIG. 27 is a longitudinal sectional view used for describing operationof a lens holder for holding an objective lens in an electronicendoscope shown in FIG. 23.

FIG. 28 is a schematic diagram used for describing a view field regionin an electronic endoscope shown in FIG. 23.

FIG. 29 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 30 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 29.

FIG. 31 is an exploded perspective view of an electronic endoscope shownin FIG. 29.

FIG. 32 is a longitudinal sectional view used for describing operationof a lens holder for holding an objective lens in an electronicendoscope shown in FIG. 29.

FIG. 33 is a longitudinal sectional view used for describing operationof a lens holder for holding an objective lens in an electronicendoscope shown in FIG. 29.

FIG. 34 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 35 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 34.

FIG. 36 is an exploded perspective view of an electronic endoscope shownin FIG. 34.

FIG. 37 is an enlarged perspective view of a part containing an imagepick-up drive unit part of an electronic endoscope.

FIG. 38A is an enlarged perspective view showing a situation of movementof a lens holder inside a transparent cover in a state that the lensholder is located at an upper end position.

FIG. 38B is an enlarged perspective view showing a situation of movementof a lens holder inside a transparent cover in a state that the lensholder is located at a lower end position.

FIG. 39A is an enlarged perspective view showing a main part of a movingmechanism for a lens holder in a state that the lens holder is locatedat an upper end position.

FIG. 39B is an enlarged perspective view showing a main part of a movingmechanism for a lens holder in a state that the lens holder is locatedat a lower end position.

FIG. 40 is a sectional perspective view of a part showing a mode ofsupporting an upper end of a feed screw shown in FIG. 39A.

FIG. 41 is a functional block diagram showing an image pick-up driveunit part

FIG. 42 is an explanation diagram showing a situation of a view fieldregion of an objective lens group.

FIG. 43 is a flow chart showing a processing procedure of a controlprogram.

FIG. 44 is an explanation diagram showing a situation that an image mapis generated from a plurality of pick-up images.

FIG. 45 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 46 is an exploded perspective view of an electronic endoscope shownin FIG. 45.

FIG. 47 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 45.

FIG. 48 is an enlarged perspective view of a part containing an imagepick-up drive unit part of an electronic endoscope shown in FIG. 45.

FIG. 49 is a functional block diagram showing a control unit mounted onan electronic endoscope shown in FIG. 45.

FIG. 50 is a flow chart showing a processing procedure of a controlprogram executed by a CPU shown in FIG. 49.

FIG. 51 is a longitudinal sectional view showing a state that a lensholder has gone half around from a state shown in FIG. 47.

FIG. 52 is a longitudinal sectional view showing a state that a lensholder shown in FIG. 51 has been lowered to an image pick-up completionposition.

FIG. 53 is a diagram showing a situation of movement of a field of viewof image pick-up of an objective lens shown in FIG. 47.

FIG. 54 is a functional block diagram showing a control unit serving asan alternative of that shown in FIG. 49.

FIG. 55 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 56 is an exploded perspective view of an electronic endoscope shownin FIG. 55.

FIG. 57 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 55.

FIG. 58 is a plan view for describing a method of image pick-upperformed using an electronic endoscope shown in FIG. 55.

FIG. 59 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 60 is an exploded perspective view of an electronic endoscope shownin FIG. 59.

FIG. 61 is a schematic diagram showing a state that an electronicendoscope shown in FIG. 59 is inserted into a hole serving as a subject.

FIG. 62 is a functional block diagram showing a control unit mounted onan electronic endoscope shown in FIG. 59.

FIG. 63 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 64 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 65 is an exploded perspective view of an electronic endoscope shownin FIG. 64.

FIG. 66 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 64.

FIG. 67 is a functional block diagram showing a control unit mounted onan electronic endoscope shown in FIG. 64.

FIG. 68 is a longitudinal sectional view showing a state that a lensholder has gone half around from a state shown in FIG. 66.

FIG. 69 is a longitudinal sectional view showing a state that a lensholder shown in FIG. 66 has been lowered to an image pick-up completionposition.

FIG. 70 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 71 is an exploded perspective view of an electronic endoscope shownin FIG. 70.

FIG. 72 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 70.

FIG. 73 is a functional block diagram showing a first control unitmounted on an electronic endoscope shown in FIG. 70.

FIG. 74 is a functional block diagram showing a second control unitmounted on an electronic endoscope shown in FIG. 70.

FIG. 75 is a flow chart showing a processing procedure of a controlprogram executed by a CPU shown in FIG. 74.

FIG. 76 is a longitudinal sectional view showing a state that a lensholder has been lowered to an image pick-up completion position.

FIG. 77 is a diagram showing a situation of movement of a field of viewof image pick-up of an objective lens shown in FIG. 72.

FIG. 78 is a longitudinal sectional view showing a state that a lensholder has gone half around from a state shown in FIG. 72.

FIG. 79 is a longitudinal sectional view showing a state that a lensholder has gone one around from a state shown in FIG. 72.

FIG. 80 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 81 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 80.

FIG. 82 is an exploded perspective view of an electronic endoscope shownin FIG. 80.

FIG. 83 is an enlarged perspective view showing a main part of anelectronic endoscope shown in FIG. 80.

FIG. 84A is an enlarged perspective part view showing operation of amoving lens frame provided with an objective lens in a state that themoving lens frame is located at a raised position.

FIG. 84B is an enlarged perspective part view showing operation of amoving lens frame provided with an objective lens in a state that themoving lens frame is located at a lowered position.

FIG. 85A is a sectional view showing operation of a moving lens frameprovided with an objective lens in a state of having gone half aroundfrom a revolution start position.

FIG. 85B is a sectional view showing operation of a moving lens frameprovided with an objective lens in a state of having gone one aroundfrom a revolution start position.

FIG. 85C is a sectional view showing operation of a moving lens frameprovided with an objective lens in a state of being located at aretarded position where revolution has been completed.

FIG. 86 is a functional block diagram showing an image pick-up driveunit part.

FIG. 87 is a flow chart showing a processing procedure of a controlprogram stored in a memory.

FIG. 88 is a diagram illustrating movement of a field of view of imagepick-up of an objective lens in a case that image pick-up steps areexecuted repeatedly.

FIG. 89A is a schematic diagram showing a situation that the inside of asubject is observed

FIG. 89B is a schematic diagram showing a situation that the inside of asubject is observed.

FIG. 89C is a schematic diagram showing a situation that the inside of asubject is observed.

FIG. 90 is an external appearance perspective view of another example ofan electronic endoscope used for describing an embodiment of the presentinvention.

FIG. 91 is an exploded perspective view of an electronic endoscope shownin FIG. 90.

FIG. 92 is a longitudinal sectional view of an electronic endoscopeshown in FIG. 90.

FIG. 93 is a longitudinal sectional view showing a state that a lensholder of an electronic endoscope shown in FIG. 90 has gone half aroundfrom a state shown in FIG. 92.

FIG. 94 is a longitudinal sectional view showing a state that a lensholder of an electronic endoscope shown in FIG. 90 has gone to a mostlowered position.

FIG. 95 is a functional block diagram showing an electronic endoscopeshown in FIG. 90.

FIG. 96 is a flow chart showing a processing procedure of a controlprogram executed by a control section of an electronic endoscope shownin FIG. 90.

FIG. 97 is a schematic diagram showing a situation of movement of afield of view of image pick-up of an electronic endoscope shown in FIG.90.

DESCRIPTION OF EMBODIMENTS

An electronic endoscope 1 shown in FIGS. 1 to 3 has an outer shellconstructed from a body part 11 and a transparent cover 13. Then, itsinside is provided with: a lens holder 19 that holds an objective lens17 for focusing object light through the transparent cover 13; a drivingsection 21 for moving the lens holder 19 inside the outer shell; and asolid-state imaging device 23 that receives the object light acquiredthrough the objective lens 17 and then converts the light into anelectric signal.

The body part 11 constituting a part of the outer shell is fabricatedfrom resin material or the like having light shielding property andformed into a cylindrical shape whose one-end part 11 a is closed andwhose the other end part 11 c is open. The closed end part (bottom part)11 a is provided with a tube-shaped battery accommodating part 11 b. Thebattery accommodating part 11 b is closed by a battery lid 27 after apower battery 25 is mounted.

That is, the electronic endoscope 1 is provided with the power battery25 in the inside, and hence does not require other power supply from theoutside. Thus, the electronic endoscope 1 need not be connected to apower supply cable, and hence permits easy handling.

Here, in the example shown in the figure, in the bottom part 11 a, twopipes 29 protrude outward from the outer shell. For example, in a casethat image data and an image map stored in a memory 83 described laterare to be transferred to an external device, data transfer cables areinserted through and protected by the pipes 29. The pipes 29 may befabricated from soft material, or alternatively may be fabricated fromhard material so as to serve as a grip used for inserting or extractingthe electronic endoscope 1 into or from a hole serving as a subject, orfor rotating the electronic endoscope 1 during the use of the electronicendoscope 1.

The transparent cover 13 formed in a cylindrical shape whose one-endpart 13 b is open. In the transparent cover 13, the open end part 13 bis aligned with the open end part 11 c of the body part 11, and thenfixed to the body part 11 by appropriate means such as bonding. Here, inthe electronic endoscope 1, the shape of the body part 11 and thetransparent cover 13 serving as an outer shell need not be a cylinderand may be a tube of another kind.

The other end part (tip part) 13 a of the transparent cover 13 is formedin a smooth hemispherical shape for permitting easy insertion into ahole serving as a subject. Then, the tip part 13 a and the open end part13 b are connected by a cylindrical part 13 c having the same diameteras the tip part 13 a. The tip part 13 a and the cylindrical part 13 care formed in a smaller diameter than the open end part 13 b. As such,since the hemispherically formed tip part 13 a and the cylindrical part13 c are formed in a small diameter, easy insertion into a relativelynarrow hole serving as a subject is achieved so that the range ofapplication of the electronic endoscope 1 is expanded.

The transparent cover 13 having the above-mentioned configuration isfabricated from transparent resin material or the like by integralmolding or the like. Alternatively, the hemispherically formed tip part13 a, the open end part 13 b, and the cylindrical part 13 c may befabricated as separate members, and then may be joined to each other byappropriate means as such bonding. In this case, at least thecylindrical part 13 c serving as a window part facing the innerperipheral surface of a hole serving as a subject is formed transparent.Here, in the present invention, the term “transparent” indicates thatthe material is transparent to light at a particular wavelengthsensitive to the imaging device 23. That is, the material need not betransparent to visible light.

The lens holder 19 is formed from resin material or the like and has: adisk-shaped flange 33 fit into the body part 11; and a tube-shaped part15 formed in a smaller diameter than the flange 33 and capable ofentering the cylindrical part 13 c of the transparent cover 13. In theflange 33, its outer diameter is formed somewhat smaller than the innerdiameter of the body part 11. Thus, the flange 33 moves in the inside ofthe body part 11 along the center axis of the body part 11, that is,along the center axis of the outer shell, smoothly without chattering.Further, in the tube-shaped part 15, its outer diameter is formedsomewhat smaller than the inner diameter of the cylindrical part 13 c ofthe transparent cover 13. Thus, the tube-shaped part 15 moves in theinside of the cylindrical part 13 c along the center axis of the outershell smoothly without chattering.

In the flange 33 of the lens holder 19, engagement grooves 35 are formedin the outer peripheral surface. The inner peripheral surface of thebody part 11 is provided with ribs 31 extending along the axis of theouter shell. Then, in the lens holder 19, the engagement grooves 35 ofthe flange 33 are engaged with the ribs 31 of the body part 11. Thus,movement of the lens holder 19 is guided in parallel to the center axisof the outer shell. That is, revolution about a feed screw 67 describedlater is stopped. Here, in the example shown in the figure, twoengagement grooves 35 are provided at intervals in the circumferentialdirection. However, the number of such grooves need not be two.

In the tip part of the tube-shaped part 15, an objective mirror 16 isaccommodated. The objective mirror 16 has a shape obtained by cutting acylinder with an included plane intersecting the center axis at 45degrees. Then, the inclined surface is fabricated in the form of areflecting surface by formation of a reflection film or the like.

Further, in the tube-shaped part 15, an image pick-up hole is formed ata site radially facing the reflecting surface of the objective mirror16. Then, the objective lens 17 is mounted inside the image pick-uphole. Then, object light is focused along the cylindrical part 13 c ofthe transparent cover 13 by the objective lens 17 so as to travel to theobjective mirror 16 in the form of a parallel light beam. Then, theobject light is reflected by the reflecting surface of the objectivemirror 16, and then travels along the center axis of the tube-shapedpart 15 in parallel to the center axis of the outer shell withmaintaining the form of a parallel light beam.

In the inside of the body part 11, an image pick-up drive unit part 37is arranged at a position located on an extended line of the center axisof the tube-shaped part 15 of the lens holder 19. The image pick-updrive unit part 37 is fixed inside the body part 11 by a fixing member(not shown). The image pick-up drive unit part 37 has three base plates41, 42, and 43.

FIG. 4 shows the image pick-up drive unit part 37 in an enlarged view.The solid-state imaging device 23 is provided on a base plate 43arranged most adjacent to the lens holder 19. The imaging device 23 maybe a CCD type imaging device, a CMOS type imaging device, or the like. Amemory 83 is mounted on a base plate 42 arranged under the base plate 43(on the bottom part 11 a side of the body part 11). The memory 83 storesimage data and the like generated from image pick-up signals read outfrom the imaging device 23. Further, a control unit 45 is mounted on abase plate 41 arranged under the base plate 42. The control unit 45performs, for example, read of image pick-up signals from the imagingdevice 23 and generation of image data on the basis of the read-outimage pick-up signals.

The imaging device 23 is arranged on the base plate 43 at a positionlocated on an extended line of the center axis of the tube-shaped part15 of the lens holder 19. Then, a focusing lens 51 is arranged at aposition located above the imaging device 23 and located on an extendedline of the center axis of the tube-shaped part 15. The focusing lens 51is held by a focusing lens holder 49 provided on the base plate 43 in amanner of surrounding the imaging device 23. The focusing lens 51 causesthe object light L1 traveling in the form of a parallel light beam alongthe center axis of the tube-shaped part 15 to be focused on the lightacceptance surface of the imaging device 23 so that image formation isachieved. That is, the objective lens 17, the objective mirror 16, andthe focusing lens 51 constitute an objective optical system.

Further, a half mirror 53 is arranged on the optical path of the objectlight between the objective mirror 16 accommodated in the tube-shapedpart 15 of the lens holder 19 and the focusing lens 51. The half mirror53 allows transmission of at least a part of the object light travelingfrom the objective mirror 16 toward the focusing lens 51. Further, at aposition located outside the optical path of the object light betweenthe objective mirror 16 and the focusing lens 51 and that faces the halfmirror 53, a light emitting diode (LED) 55 is provided that serves as alight source for illuminating the image-taking object. Light forillumination L2 projected from the LED 55 is brought into the form of aparallel light beam by an illumination lens 57 arranged between the LED55 and the half mirror 53, and then enters the half mirror 53 so that atleast a part of the light is reflected toward the objective mirror 16.Then, the light for illumination having entered the objective mirror 16is reflected toward the objective lens 17, and then projected throughthe objective lens 17 and the transparent cover 13 onto the image-takingobject. Here, the half mirror 53, the LED 55, and the illumination lens57 are fixed inside the body part 11 individually by appropriate fixingmembers.

Here, the movement of the lens holder 19 is guided along the center axisof the outer shell by the above-mentioned engagement between theengagement grooves 35 of the flange 33 and the ribs 31 of the body part11. Then, the lens holder 19 whose movement is guided along the centeraxis of the outer shell is allowed to move such that the objective lens17 held in the tube-shaped part 15 moves between height h1 shown in FIG.5A and height hn shown in FIG. 5B. In the following, the driving section21 for moving the lens holder 19 is described in detail with referenceto FIGS. 3, 6A, 6B, and 7.

The inside of the body part 11 is provided with: a feed screw 67arranged in parallel to the center axis of the outer shell; and astepping motor 61 serving as a source of power for driving and revolvingthe feed screw 67. A motor gear wheel 63 is integrally attached to theshaft of the stepping motor 61, and a gear wheel 69 is integrallyattached to one-end part of the feed screw 67. Then, between the motorgear wheel 63 and the gear wheel 69, an idle gear wheel 65 is providedsuch as to engage with these gear wheels 63 and 69. The stepping motor61 and the idle gear wheel 65 are fixed inside the body part 11 byappropriate fixing members. Further, as shown in FIG. 7, in the feedscrew 67, its one-end part is inserted into a shaft hole 13 d formed inthe flange face of the open end part 13 b of the transparent cover 13,while the other end part is supported by a support arm 71 provided inthe side face of the focusing lens holder 49 of the image pick-up driveunit part 37, so that the feed screw 67 is revolvable about the centeraxis.

The revolution of the stepping motor 61 is transmitted through the motorgear wheel 63, the idle gear wheel 65, and the gear wheel 69 to the feedscrew 67. Here, the idle gear wheel 65 has a larger number of gear teeththan the motor gear wheel 63. Thus, the revolution of the stepping motor61 is slowed down and then transmitted to the idle gear wheel 65. Here,the employed source of power for driving and revolving the feed screw 67is not limited to a stepping motor operated by pulse drive, and may be amotor of a diverse kind such as a servo motor provided with an encoder,or alternatively may be a power source of another type.

On the other hand, in the flange 33 of the lens holder 19, athrough-hole 73 is formed that allows the stepping motor 61, the motorgear wheel 63, the idle gear wheel 65, the feed screw 67, the gear wheel69, and the like to pass through. Then, in the lens holder 19, a feednut 75 screwed onto the feed screw 67 is attached integrally by a nutholding piece 77. As described above, the lens holder 19 is guided suchthat movement in the up and down directions in the figure is permittedalong the center axis of the outer shell and that revolution movementabout the feed screw 67 is restricted. Thus, in association withrevolution of the feed screw 67, the feed nut 75 screwed on the feedscrew 67 and the lens holder 19 that holds the feed nut 75 move alongthe feed screw 67, that is, along the center axis of the outer shell.

For example, in a situation that the lens holder 19 is located at araised position shown in FIG. 6A, the stepping motor 61 is revolved in apredetermined direction so that the feed screw 67 is revolved via themotor gear wheel 63, the idle gear wheel 65, and the gear wheel 69. Inassociation with the revolution of the feed screw 67, the feed nut 75moves along the feed screw 67. By virtue of this, the lens holder 19formed integrally with the feed nut 75 is lowered to the loweredposition shown in FIG. 6B.

FIG. 8 is a functional block diagram showing the image pick-up driveunit part 37. In the image pick-up drive unit part 37, the control unit45 has: an LED drive circuit 85 for driving the LED 55; an imagingdevice driver 87 for driving the imaging device 23; a motor driver 89for driving the stepping motor 61; a pulse generator 91 for providingdriving pulses to the motor driver 89; and a control section 81 forcontrolling the operation of the LED drive circuit 85, the imagingdevice driver 87, and the pulse generator 91. Further, the memory 83stores a control program for the control unit 45. Here, in addition tothe storing of a control program, the memory 83 stores image data andserves also as a work memory. The control section 81 performsappropriate image processing onto image pick-up signals read from theimaging device 23, so as to generate image data, and then stores thegenerated image data into the memory 83. This configuration allows theelectronic endoscope 1 in a stand alone mode to acquire and save imagesof image-taking objects. This provides excellence in easy handling.

When the power switch 93 of the electronic endoscope 1 is closed,electric power from the power battery 25 is supplied through wiring (notshown) to the individual parts of the image pick-up drive unit part 37,so that image pick-up is performed. For example, the power switch 93 maybe provided in the bottom part 11 a of the body part 11, and may beopened or closed by manual operation. Alternatively, a switch terminalthat follows magnetism may be built in the body part 11. Then, from theoutside of the electronic endoscope 1, a magnet may be brought close orapart so that the switch terminal may be opened or closed.

Next, the operation of the electronic endoscope 1 is described below.When the power switch 93 is turned ON, electric power is supplied fromthe power battery 25 to the individual parts. Then, light forillumination is projected from the LED 55 through the objective lens 17and the cylindrical part 13 c of the transparent cover 13 toward a sidedirection so that an image-taking object is illuminated.

Reflected light from the image-taking object is acquired into theelectronic endoscope 1 through the cylindrical part 13 c of thetransparent cover 13 and the objective lens 17, so that an image isformed onto the light acceptance surface of the imaging device 23 by thefocusing lens 51. Then, charge accumulated in the imaging device 23 as aresult of photoelectric conversion is read as an image pick-up signal bythe control section (CPU) 81 of the control unit 45. The control section81 performs appropriate image processing onto the read-out image pick-upsignal so as to generate image data, and then stores the generated imagedata into the memory 83.

FIG. 9 is a flow chart showing the processing procedure of a controlprogram of the control unit 45 When the power switch 93 is turned ON,first, the stepping motor 61 is driven and revolved, so that the lensholder 19 goes along the center axis of the outer shell of theelectronic endoscope 1 to a home position (step S1). Here, the homeposition indicates, for example, the position shown in FIG. 5A where theobjective lens 17 is located on the tip side of the electronic endoscope1. However, the definition is not limited to this. That is, the homeposition may be defined as the opposite position where the objectivelens 17 is located on the pedestal side (the position shown in FIG. 5B).

After the lens holder 19 is set at the home position, image pick-upprocessing is performed (step S2). The image pick-up processing includessuch processes that: the LED 55 is driven so as to emit light forillumination; object light is acquired through the objective lens 17into the electronic endoscope 1 so that an image is formed onto thelight acceptance surface of the imaging device 23; and on the basis ofthe image pick-up signal read from the imaging device 23, image data isgenerated and then stored into the memory 83.

Then, the stepping motor 61 is driven by a specified number of pulses(step S3), so that the lens holder 19 is lowered by a predetermineddistance. Until the lens holder 19 reaches the most lowered position(step S4), image pick-up processing is performed at each destination ofthe movement (step S2). When the lens holder 19 reaches the most loweredposition, the lowering operation of the lens holder 19 and the imagepick-up processing are terminated (step S4). Here, in the electronicendoscope 1, the plural pieces of image data stored in the memory 83 arecombined into an image map as shown in FIG. 10 (step S5).

In the image map shown in FIG. 10, the image data IMG(1) indicates imagedata acquired in the first occasion of image pick-up operation, whichwas taken over the view field region W1 in a situation that theobjective lens 17 was located at height h1 shown in FIG. 5A. Further,the image data IMG(2) indicates image data acquired in the secondoccasion of image pick-up operation, which was taken over the view fieldregion W2 in a situation that the objective lens 17 was lowered togetherwith the lens holder 19 by a predetermined distance and thereby locatedat height h2.

As such, plural pieces of image data IMG(1) to IMG(n) each obtained ateach position of the movement of the lens holder 19 are combined into asubstantially single sheet of image data (image map) by linking the datapieces sequentially in the order of image pick-up in the movingdirection of the lens holder 19. Here, for example, the number of pulsesprovided to the stepping motor 61 at step S3 may be adjustedappropriately, or alternatively the screw pitch of the feed screw 67 maybe adjusted appropriately, such that a part of the view field region inthe present occasion of image pick-up processing should overlap with theview field region in the preceding occasion of image pick-up processing.By virtue of this, images of the image-taking object are acquiredwithout a missing part in the axial direction so that an image mapwithout a gap is obtained.

When the above-mentioned image map has been generated, the image map isto be read from the memory 83 to the outside (see FIG. 8). This read maybe performed by wireless, or alternatively through a cable in aconfiguration that a data transfer cable is inserted through the pipe 29shown in FIG. 1 and connected to the image pick-up drive unit part 37.Alternatively, the memory 83 may be provided in a removable manner fromthe electronic endoscope 1. Then, the removed memory 83 may be read by apersonal computer provided separately.

Further, the electronic endoscope 1 may transmit the image data to anexternal monitor, so that the image may be observed on line through theexternal monitor. In addition, operation instructions may be inputtedfrom the outside. In this case, without performing image processing, thecontrol section 81 transmits the image pick-up signal acquired from theimaging device 23, to an external video processor in an intact manner.Then, an object image obtained by image processing by the videoprocessor is displayed on the external monitor. The communicationbetween the external video processor, the external monitor, and thecontrol section 81 may be of cable or wireless. In a case that thecommunication is of cable, an external power source becomes employablewhen a power source line is included in the wiring.

Further, as another example of the control program, a control programmay be employed that, in addition to the control procedure shown in theflow chart of FIG. 9, allows the view field region of the objective lens17 to be moved to an arbitrary position in accordance with an operationinstruction from the outside. In this case, selective image pick-up of adesired site is achieved in accordance with the purpose of imagepick-up, and hence more detailed observation of the site is allowed.

According to the electronic endoscope 1 described above, after beinginstalled inside a hole, the objective lens 17 is moved in the axialdirection by the driving section 21. In association with this, the fieldof view moves in the axial direction. This permits accurate acquisitionof an image over a large region of the inner peripheral surface of thehole, without the necessity of a skill in the operation.

An electronic endoscope 101 shown in FIGS. 11 to 13 has an outer shellconstructed from a body part 11 and a transparent cover 13. Then, itsinside is provided with: a lens holder 119 that holds an objective lensgroup 117 for focusing object light through the transparent cover 13; adriving section 21 for moving the lens holder 119 inside the outershell; and a solid-state imaging device 23 that receives the objectlight acquired through the objective lens group 117 and then convertsthe light into an electric signal. Here, like members to those of theelectronic endoscope 1 described above are designated by like numerals,and functionally common members are designated by appropriatelycorresponding numerals. Then, their description is omitted orsimplified.

The lens holder 119 is formed from resin material or the like and has: adisk-shaped flange 33 fit into the body part 11; and a tube-shaped part115 formed in a smaller diameter than the flange 33 and capable ofentering the cylindrical part 13 c of the transparent cover 13. Theflange 33 moves in the inside of the body part 11 along the center axisof the body part 11, that is, along the center axis of the outer shell,smoothly without chattering. Further, the tube-shaped part 115 moves inthe inside of the cylindrical part 13 c along the center axis of theouter shell smoothly without chattering.

In the electronic endoscope 101, the objective lens group 117 held bythe lens holder 119 includes a wide-angle lens and constructed from awide-angle lens 117A and a lens 117B. Preferably, the wide-angle lens117A is composed of a fish-eye lens. In this case, a circular fish-eyelens is suitable for observation in the entire circumferentialdirections where the inclination angle (angle relative to the lensoptical axis) is large. That is, the wide-angle lens of the presentinvention is a wide-angle lens having an observational field of viewthat permits observation in the entire side circumferential directionsaround the optical axis (the center axis of the tube-shaped part 115) ofthe objective lens group 117. Here, in addition to this configuration,the wide-angle lens 117A may be composed of a diagonal fish-eye lens, acommon wide-angle lens, or the like. The objective lens group 117 isattached to the opening part on the tip side of the tube-shaped part 115in a state that its lens optical axis agrees with the center axis of thetube-shaped part 115 of the lens holder 119.

Object light is focused along the cylindrical part 13 c of thetransparent cover 13 into the form of a parallel light beam by theobjective lens group 117, and then travels along the center axis of thetube-shaped part 115 in parallel to the center axis of the outer shell.In the inside of the body part 11, the image pick-up drive unit part 37is arranged at a position located on an extended line of the center axisof the tube-shaped part 115 of the lens holder 119. The image pick-updrive unit part 37 and the driving section 21 for moving the lens holder119 are the same as those of the electronic endoscope 1 described above.Thus, their description is omitted.

Next, the operation of the electronic endoscope 101 is described below.With reference to FIG. 8, the power switch 93 is turned ON so thatelectric power is supplied from the power battery 25 to the individualparts. Then, light for illumination is projected from the LED 55 throughthe objective lens group 117 and the cylindrical part 13 c of thetransparent cover 13 toward a side direction so that an image-takingobject is illuminated. Reflected light from the image-taking object isacquired into the electronic endoscope 1 through the cylindrical part 13c of the transparent cover 13 and the objective lens group 117, so thatan image is formed onto the light acceptance surface of the imagingdevice 23 by the focusing lens 51.

FIG. 14 shows the situation of the view field region W formed by theobjective lens group 117. The light for illumination emitted from thewide-angle lens 117A is projected onto the region indicated as the viewfield region W. Among the reflected light from the image-taking objectilluminated by the light for illumination, the part of light belongingto the view field region W is used in image formation and then acquiredby the imaging device 23. Here, symbol M indicates a mask for limitingthe view field region into W.

Then, charge accumulated in the imaging device 23 as a result ofphotoelectric conversion is read as an image pick-up signal by thecontrol section (CPU) 81 of the control unit 45. The control section 81performs appropriate image processing onto the read-out image pick-upsignal so as to generate image data, and then stores the generated imagedata into the memory 83.

The control program for the electronic endoscope 101 is the same as thatfor the electronic endoscope 1 described above. Thus, with reference toFIG. 9, when the power switch 93 is turned ON, first, the stepping motor61 is driven and revolved so that the lens holder 119 goes along thecenter axis of the outer shell of the electronic endoscope 1 to a homeposition (step S1). After the lens holder 119 is set at the homeposition, image pick-up processing is performed (step S2).

Then, the stepping motor 61 is driven by a specified number of pulses(step S3), so that the lens holder 119 is lowered by a predetermineddistance. Here, the predetermined distance indicates a step distance bywhich the lens holder 119 is to be moved stepwise in order that the viewfield region W shown in FIG. 14 should cover stepwise the movable regionof the lens holder 119. For example, the predetermined distance may bethe height La of a part contained in the view field region W in thecylindrical part 13 c of the transparent cover 13.

Until the lens holder 119 reaches the most lowered position (step S4),image pick-up processing is performed at each destination of themovement (step S2). When the lens holder 119 reaches the most loweredposition, the lowering operation of the lens holder 119 and the imagepick-up processing are terminated (step S4). Here, also in theelectronic endoscope 101, the plural pieces of image data stored in thememory 83 are combined into an image map as shown in FIG. 15 (step S5).

In the image map shown in FIG. 15, the image data IMG(1) indicates imagedata that was acquired in the first occasion of image pick-up operation,which was taken over the view field region W1 in the entire directions(circumferential angle from 0 degree to 360 degrees) in a situation thatthe objective lens group 117 is at height h1. Further, the image dataIMG(2) indicates image data acquired in the second occasion of imagepick-up operation, which was taken over the view field region W2 in theentire directions in a situation that the objective lens group 117 waslowered together with the lens holder 119 by a predetermined distanceand thereby located at height h2. As such, plural pieces of image dataIMG(1) to IMG(n) each obtained at each position of the movement of thelens holder 119 are combined into a substantially single sheet of imagedata (image map) by linking the data pieces sequentially in the order ofimage pick-up in the moving direction of the lens holder 119.

According to the electronic endoscope 101, the objective lens group 117includes the wide-angle lens 117A. This permits image pick-up over alarger region in the circumferential direction in comparison with thecase of the electronic endoscope 1. In particular, when a fish-eye lensis employed, image pick-up is achieved in the entire directions.

An electronic endoscope 201 shown in FIGS. 16 to 18 has an outer shellconstructed from a body part 11 and a transparent cover 13. Then, itsinside is provided with: a lens holder 219 that holds an objective lens17 for focusing object light through the transparent cover 13; a drivingsection 221 for moving the lens holder 219 in the axial direction insidethe outer shell; and a solid-stare imaging device 23 that receives theobject light acquired through the objective lens 17 and then convertsthe light into an electric signal. Here, like members to those of theelectronic endoscope 1 described above are designated by like numerals,and functionally common members are designated by appropriatelycorresponding numerals. Then, their description is omitted orsimplified.

The lens holder 219 is formed from resin material or the like and has: adisk-shaped flange 233 fit into the body part 11; and a tube-shaped part215 formed in a smaller diameter than the flange 233 and capable ofentering the cylindrical part 13 c of the transparent cover 13. Theflange 233 moves in the inside of the body part 11 along the center axisof the body part 11, that is, along the center axis of the outer shell,smoothly without chattering. Further, the tube-shaped part 215 moves inthe inside of the cylindrical part 13 c along the center axis of theouter shell smoothly without chattering.

The tube-shaped part 215 and the flange 233 are formed separately fromeach other. Then, the tube-shaped part 215 is attached to the flange233. In the center part of the flange 233, a hollow cylindrical shaft236 is provided in a protruding manner. The tube-shaped part 215 isattached to the flange 233 in a state that the pedestal part of thetube-shaped part 215 is fit outside the shaft 236. Thus, the tube-shapedpart 215 is supported in a revolvable manner about the shaft 236.

In the flange 233 of the lens holder 219, engagement grooves 235 areformed in the outer peripheral surface. The inner peripheral surface ofthe body part 11 is provided with ribs 31 extending along the axis ofthe outer shell. Then, in the lens holder 219, the engagement grooves235 of the flange 233 are engaged with the ribs 31 of the body part 11.Thus, movement of the lens holder 219 is guided in parallel to thecenter axis of the outer shell. That is, revolution about a feed screw67 described later is stopped.

On the tip side of the tube-shaped part 215, an objective mirror 16 isaccommodated. Further, in the tube-shaped part 215, an image pick-uphole is formed at a site radially facing the reflecting surface of theobjective mirror 16. Then, the objective lens 17 is mounted inside theimage pick-up hole. Then, object light is focused along the cylindricalpart 13 c of the transparent cover 13 by the objective lens 17 so as totravel to the objective mirror 16 in the form of a parallel light beam.Then, the object light is reflected by the reflecting surface of theobjective mirror 16, and then travels along the center axis of thetube-shaped part 215 in parallel to the center axis of the outer shellwith maintaining the form of a parallel light beam.

In the inside of the body part 11, an image pick-up drive unit part 37is arranged at a position located on an extended line of the center axisof the tube-shaped part 15 of the lens holder 19. The image pick-updrive unit part 37 is the same as that of the electronic endoscope 1described above. Thus, description is omitted.

Here, the movement of the lens holder 219 is guided along the centeraxis of the outer shell by the above-mentioned engagement between theengagement grooves 235 of the flange 233 and the ribs 31 of the bodypart 11. The driving section 221 for moving the lens holder 219 alongthe center axis of the outer shell is described below in detail withreference to FIGS. 18 and 19.

The inside of the body part 11 is provided with: a feed screw 67arranged in parallel to the center axis of the outer shell; and astepping motor 61 serving as a source of power for driving and revolvingthe feed screw 67. A motor gear wheel 63 is attached to the shaft of thestepping motor 61, and a gear wheel 69 is attached to one-end part ofthe feed screw 67. Then, between the motor gear wheel 63 and the gearwheel 69, an idle gear wheel 65 is provided such as to engage with thesegear wheels 63 and 69. The revolution of the stepping motor 61 istransmitted through the motor gear wheel 63, the idle gear wheel 65, andthe gear wheel 69 to the feed screw 67.

On the other hand, in the flange 233 of the lens holder 219, athrough-hole 73 is formed that allows the stepping motor 61, the motorgear wheel 63, the idle gear wheel 65, the feed screw 67, the gear wheel69, and the like to pass through. Then, in the periphery of thethrough-hole 73 of the flange 233, a feed nut 75 screwed onto the feedscrew 67 is attached by a nut holding piece 77. As described above, inthe lens holder 219, movement is guided along the center axis of theouter shell, that is, revolution about the feed screw 67 is stopped.Thus, in association with revolution of the feed screw 67, the feed nut75 screwed on the feed screw 67 and the lens holder 219 that holds thefeed nut 75 move along the feed screw 67, that is, along the center axisof the outer shell.

Further, in the driving section 221, a shaft 268 arranged in parallel tothe feed screw 67 is provided. In the shaft 268, an external-tooth gearis formed in the outer peripheral surface and engages with the gearwheel 69 fixed to the feed screw 67, and hence revolves about the centeraxis together with the feed screw 67. Then, in the pedestal part of thetube-shaped part 215, a gear wheel 270 engaging with the shaft 268 isfixed by appropriateness means such as press fit and bonding. Inaccordance with the revolution of the feed screw 67, the gear wheel 270of the tube-shaped part 215 moves in the axial direction together withthe lens holder 219 and maintains the engagement with the shaft 268.Then, the tube-shaped part 215 is driven and revolved through the shaft268 and the gear wheel 270.

For example, in a situation that the lens holder 219 is located at araised position shown in FIG. 20, the stepping motor 61 is revolved in apredetermined direction so that the feed screw 67 is revolved via themotor gear wheel 63, the idle gear wheel 65, and the gear wheel 69. Inassociation with the revolution of the feed screw 67, the feed nut 75moves along the feed screw 67. As a result, the lens holder 219 islowered.

Then, as shown in FIG. 21, during the course that the lens holder 219 islowered by Δh, the tube-shaped part 215 is revolved via the shaft 268and the gear wheel 270 by a predetermined angle. In accordance with therevolution of the tube-shaped part 215, the objective lens 17 is alsorevolved so that the field of view of image pick-up moves in thecircumferential direction.

Next, the operation of the electronic endoscope 201 is described below.With reference to FIG. 8, the power switch 93 is turned ON so thatelectric power is supplied from the power battery 25 to the individualparts. Then, light for illumination is projected from the LED 55 throughthe objective lens 17 and the cylindrical part 13 c of the transparentcover 13 toward a side direction so that an image-taking object isilluminated. Reflected light from the image-taking object is acquiredinto the electronic endoscope 201 through the cylindrical part 13 c ofthe transparent cover 13 and the objective lens 17, so that an image isformed onto the light acceptance surface of the imaging device 23 by thefocusing lens 51. Then, charge accumulated in the imaging device 23 as aresult of photoelectric conversion is read as an image pick-up signal bythe control section (CPU) 81 of the control unit 45. The control section81 performs appropriate image processing onto the read-out image pick-upsignal so as to generate image data, and then stores the generated imagedata into the memory 83.

The control program for the electronic endoscope 201 is the same as thatfor the electronic endoscope 1 described above. Thus, with reference toFIG. 9, when the power switch 93 is turned ON, first, the stepping motor61 is driven and revolved so that the lens holder 219 goes along thecenter axis of the outer shell of the electronic endoscope 201 to a homeposition (step S1). After the lens holder 219 is set at the homeposition, image pick-up processing is performed (step S2). Then, thestepping motor 61 is driven by a specified number of pulses (step S3),so that the lens holder 219 is lowered by a predetermined distance.Until the lens holder 219 reaches the most lowered position (step S4),image pick-up processing is performed at each destination of themovement (step S2). When the lens holder 219 reaches the most loweredposition, the lowering operation of the lens holder 219 and the imagepick-up processing are terminated (step S4).

FIG. 22 is a diagram illustrating the movement of the field of view ofimage pick-up achieved when the above-mentioned steps S2 to S4 areexecuted repeatedly. In the first occasion of image pick-up processingperformed at the home position, image pick-up is performed in the fieldof view “No.001”, and hence image data of the field of view “No.001” isgenerated from the image pick-up signal read from the imaging device 23.

Once the image pick-up processing in the field of view “No.001” iscompleted, the stepping motor 61 is driven at step S3 by a specifiednumber of pulses so that the lens holder 219 is lowered and thetube-shaped part 215 is revolved. As a result, the next field of view“No.002” is setup. Then, image pick-up is performed in the field of view“No.002”, and hence image data of the field of view “No.002” isgenerated from the image pick-up signal read from the imaging device 23.

After that, image pick-up processing is repeated with moving the fieldof view like “No.003”→“No.004”→“No.005” . . . . When the tube-shapedpart 215 has gone one around from the home position, the field of viewof image pick-up is located at “No.011” in FIG. 22. In case of havinggone around twice, the field of view of image pick-up is located at“No.021” in FIG. 22.

Here, for example, the number of pulses provided to the stepping motor61 at step S3 may be adjusted appropriately, or alternatively the screwpitch of the feed screw 67 may be adjusted appropriately, so thatcircumferentially adjacent fields of view of image pick-up may bepositioned such that their left and right edge parts should be incontact with each other or overlapping somewhat with each other andaxially adjacent fields of view of image pick-up may be positioned suchthat their upper and lower edge parts should be in contact with eachother or overlapping somewhat with each other. According to thisconfiguration, image taking of an object is achieved without a missingpart in the axial and the circumferential directions. Thus, an image mapwithout a gap is obtained.

According to the electronic endoscope 201, the objective lens 17 ismoved in the axial and the circumferential directions by the drivingsection 221. Then, in accordance with this, the field of view moves inthe axial and the circumferential directions. By virtue of this, imagepick-up is achieved in the entire directions without the necessity of afish-eye lens like in the electronic endoscope 101.

An electronic endoscope 301 shown in FIGS. 23 to 25 has an outer shellconstructed from a body part 11 and a transparent cover 313. Then, itsinside is provided with: a lens holder 319 that holds an objective lens17 for focusing object light through the transparent cover 313; adriving section 321 for moving the lens holder 319 inside the outershell; and a solid-state imaging device 23 that receives the objectlight acquired through the objective lens 17 and then converts the lightinto an electric signal. Here, like members to those of the electronicendoscope 1 described above are designated by like numerals, andfunctionally common members are designated by appropriatelycorresponding numerals. Then, their description is omitted orsimplified.

The transparent cover 313 formed in a cylindrical shape whose one-endpart 313 b is open. The transparent cover 313 is fixed to the body part11 in a state that the open end part 313 b is aligned with the open endpart 11 c of the body part 11. The other end part (tip part) 313 a ofthe transparent cover 313 is formed in a smooth hemispherical shape forpermitting easy insertion into a hole serving as a subject. Then, thetip part 313 a and the open end part 313 b are connected by acylindrical part 313 c having the same diameter as the tip part 313 a.In the electronic endoscope 301, the tip part 313 a and the cylindricalpart 313 c are formed in the same diameter as the open end part 313 b.

The transparent cover 313 having the above-mentioned configuration maybe fabricated, for example, by integral molding by using transparentresin material or the like. However, it is sufficient that at least thecylindrical part 313 c serving as a window part facing the innerperipheral surface of a hole serving as a subject is formed transparent.

The lens holder 319 is formed from resin material or the like and has:an objective lens mount part 314 formed in an approximately disk shape;and a tube-shaped part 315 formed in a cylindrical shape having asmaller diameter than the objective lens mount part 314. The tube-shapedpart 315 is arranged such that its center axis agrees with the centeraxis of the transparent cover 313, that is, the center axis of the outershell. The objective lens mount part 314 is provided at the tip of thetube-shaped part 315 coaxially to the tube-shaped part 315.

In the objective lens mount part 314, its outer diameter is formedsomewhat smaller than the inner diameter of the cylindrical part 313 cof the transparent cover 313. Thus, the objective lens mount part 314 isallowed to move in the inside of the transparent cover 313 smoothlywithout chattering along the center axis of the transparent cover 313,that is, the center axis of the outer shell.

In the outer peripheral surface of the tube-shaped part 315, anexternal-tooth gear 315 a is formed. The gear teeth of theexternal-tooth gear 315 a extend in parallel to the center axis of thetube-shaped part 315, and are formed at equal intervals in thecircumferential direction. Further, in the inner peripheral surface ofthe tube-shaped part 315, a female screw 315 b is formed that is screwedinto a thread groove formed in the outer peripheral surface of the feedscrew 367 described later.

In the objective lens mount part 314, a cylindrical hole 314 a is formedthat is continuous to the tip opening of the tube-shaped part 315 andextends in the axial direction of the tube-shaped part 315. Then, anobjective mirror 16 is accommodated in the cylindrical hole 314 a.Further, in the objective lens mount part 314, an image pick-up hole 314b is formed that extends in a radial direction and whose one end opensin the outer peripheral surface and whose the other end faces thereflecting surface of the objective mirror 16 in a radial direction andcommunicates with the cylindrical hole 314 a. Then, an objective lens 17is mounted in the opening part on the outer periphery side of the imagepick-up hole 314 b.

Object light is focused along the cylindrical part 313 c of thetransparent cover 313 by the objective lens 17 so as to travel to theobjective mirror 16 in the form of a parallel light beam. Then, theobject light is reflected by the reflecting surface of the objectivemirror 16, and then travels along the center axis of the tube-shapedpart 315, that is, along the center axis of the outer shell, withmaintaining the form of a parallel light beam.

In the inside of the body part 11, an image pick-up drive unit part 37is arranged at a position located on an extended line of the center axisof the tube-shaped part 315 of the lens holder 319. The image pick-updrive unit part 37 is the same as that of the electronic endoscope 1described above. Thus, description is omitted.

On the base plate 43 of the image pick-up drive unit part 37, a feedscrew 367 is attached coaxially to the tube-shaped part 315 of the lensholder 319. The feed screw 367 formed in a cylindrical shape, andaccommodates the focusing lens holder 49 in the inside. Further, thefeed screw 367 has a thread groove formed in the outer peripheralsurface. Then, in such a manner that this thread groove is screwed intothe female screw 315 b of the inner peripheral surface of thetube-shaped part 315, the feed screw 367 is inserted into thetube-shaped part 315. The object light traveling along the center axisof the tube-shaped part 315 goes into the feed screw 367, then entersthe focusing lens 51 held by the focusing lens holder 49, and then isfocused onto the light acceptance surface of the imaging device 23 bythe focusing lens 51 so that an image is formed.

Here, the LED 55 serving as a light source for illuminating theimage-taking object is arranged outside the feed screw 367. The halfmirror 53 for reflecting the light for illumination from the LED 55toward the objective mirror 16 is arranged inside the feed screw 367 andis located in the middle of the optical path of the object light. Thetube wall of the feed screw 367, which intervenes between the LED 55 andthe half mirror 53, is provided with an attachment hole. Then, theillumination lens 57 is attached in the attachment hole. The light forillumination from the LED 55 is brought into the form of a parallellight beam by the illumination lens 57, and then enters the half mirror53. Then, at least a part of the light is reflected toward the objectivemirror 16. Then, the light for illumination having entered the objectivemirror 16 is reflected toward the objective lens 17, and then projectedthrough the objective lens 17 and the transparent cover 313 onto theimage-taking object.

Here, in the lens holder 319 where its tube-shaped part 315 is screwedinto the feed screw 367, movement is guided along the feed screw 367,that is, along the center axis of the outer shell. The driving section321 for moving the lens holder 319 along the center axis of the outershell is described below in detail with reference to FIG. 24.

A stepping motor 61 is fixed inside the body part 11. Further, an idlegear wheel 65 is provided that is located between and engaging with bothof the motor gear wheel 63 of the stepping motor 61 and theexternal-tooth gear 315 a formed in the tube-shaped part 315 of the lensholder 319. The revolution of the stepping motor 61 is transmittedthrough the motor gear wheel 63 and the idle gear wheel 65 to the lensholder 319.

In the lens holder 319, the tube-shaped part 315 is fit outside the feedscrew 367. Thus, when revolution of the stepping motor 61 istransmitted, the lens holder 319 revolves about the feed screw 367. Atthe same time, the tube-shaped part 315 is screwed onto the feed screw367 by means of the female screw 315 b formed in the inner peripheralsurface. Thus, in association with revolution about the feed screw 367,the lens holder 319 moves along the feed screw 367.

For example, in a situation that the lens holder 319 is located at araised position shown in FIG. 26, the stepping motor 61 is revolved in apredetermined direction so that the lens holder 319 is revolved via themotor gear wheel 63 and the idle gear wheel 65. As a result, as shown inFIG. 27, the lens holder 319 revolves about the feed screw 367 so as togo lower by Δh along the feed screw 367. In accordance with therevolution of the lens holder 319, the objective lens 17 is alsorevolved so that the field of view of image pick-up moves in thecircumferential direction.

Next, the operation of the electronic endoscope 301 is described below.

With reference to FIG. 8, the power switch 93 is turned ON so thatelectric power is supplied from the power battery 25 to the individualparts. Then, light for illumination is projected from the LED 55 throughthe objective lens 17 and the cylindrical part 313 c of the transparentcover 313 toward a side direction so that an image-taking object isilluminated. Reflected light from the image-taking object is acquiredinto the electronic endoscope 301 through the cylindrical part 313 c ofthe transparent cover 313 and the objective lens 17, so that an image isformed onto the light acceptance surface of the imaging device 23 by thefocusing lens 51. Then, charge accumulated in the imaging device 23 as aresult of photoelectric conversion is read as an image pick-up signal bythe control section (CPU) 81 of the control unit 45. The control section81 performs appropriate image processing onto the read-out image pick-upsignal so as to generate image data, and then stores the generated imagedata into the memory 83.

The control program for the electronic endoscope 301 is the same as thatfor the electronic endoscope 1 described above. Thus, with reference toFIG. 9, when the power switch 93 is turned ON, first, the stepping motor61 is driven and revolved so that the lens holder 319 goes along thecenter axis of the outer shell of the electronic endoscope 301 to a homeposition (step S1). After the lens holder 319 is set at the homeposition, image pick-up processing is performed (step S2). Then, thestepping motor 61 is driven by a specified number of pulses (step S3),so that the lens holder 319 is lowered by a predetermined distance.Until the lens holder 319 reaches the most lowered position (step S4),image pick-up processing is performed at each destination of themovement (step S2). When the lens holder 319 reaches the most loweredposition, the lowering operation of the lens holder 319 and the imagepick-up processing are terminated (step S4).

FIG. 28 is a diagram illustrating the movement of the field of view ofimage pick-up achieved when the above-mentioned steps S2 to S4 areexecuted repeatedly. In the first occasion of image pick-up processingperformed at the home position, image pick-up is performed in the fieldof view “No.001”, and hence image data of the field of view “No.001” isgenerated from the image pick-up signal read from the imaging device 23.

Once the image pick-up processing in the field of view “No.001” iscompleted, the stepping motor 61 is driven at step S3 by a specifiednumber of pulses so that the lens holder 319 is lowered and revolved. Asa result, the next field of view “No.002” is set up. Then, image pick-upis performed in the field of view “No.002”, and hence image data of thefield of view “No.002” is generated from the image pick-up signal readfrom the imaging device 23.

After that, image pick-up processing is repeated with moving the fieldof view like “No.003”→“No.004”→“No.005” . . . . When the lens holder 319has gone one around from the home position, the field of view of imagepick-up is located at “No.011” in FIG. 28. In case of having gone aroundtwice, the field of view of image pick-up is located at “No.021” in FIG.28.

Here, for example, the number of pulses provided to the stepping motor61 at step S3 may be adjusted appropriately, or alternatively the screwpitch of the feed screw 367 may be adjusted appropriately, so thatcircumferentially adjacent fields of view of image pick-up may bepositioned such that their left and right edge parts should be incontact with each other or overlapping somewhat with each other andaxially adjacent fields of view of image pick-up may be positioned suchthat their upper and lower edge parts should be in contact with eachother or overlapping somewhat with each other. According to thisconfiguration, image taking of an object is achieved without a missingpart in the axial and the circumferential directions. Thus, an image mapwithout a gap is obtained.

According to the electronic endoscope 301, the objective lens 17 ismoved in the axial and the circumferential directions by the drivingsection 321. Then, in accordance with this, the field of view moves inthe axial and the circumferential directions. By virtue of this, imagepick-up is achieved in the entire directions without the necessity of afish-eye lens like in the electronic endoscope 101 described above.

An electronic endoscope 401 shown in FIGS. 29 to 31 has an outer shellconstructed from a body part 11 and a transparent cover 313. Then, itsinside is provided with a lens holder 419 that holds an objective lens17 for focusing object light through the transparent cover 313; adriving section 421 for moving the lens holder 419 inside the outershell; and a solid-state imaging device 23 that receives the objectlight acquired through the objective lens 17 and then converts the lightinto an electric signal. Here, like members to those of the electronicendoscope 1 or 301 described above are designated by like numerals, andfunctionally common members are designated by appropriatelycorresponding numerals. Then, their description is omitted orsimplified.

The lens holder 419 is formed from resin material or the like and has:an objective lens mount part 414 formed in an approximately disk shape;and a tube-shaped part 415 formed in a cylindrical shape having the samediameter as the objective lens mount part 414. The tube-shaped part 415is arranged such that its center axis agrees with the center axis of thetransparent cover 313, that is, the center axis of the outer shell. Theobjective lens mount part 414 is provided at the tip of the tube-shapedpart 415 coaxially to the tube-shaped part 415.

In the objective lens mount part 414 and the tube-shaped part 415, theirouter diameter is formed somewhat smaller than the inner diameter of thecylindrical part 313 c of the transparent cover 313. Thus, the objectivelens mount part 414 is allowed to move in the inside of the transparentcover 313 smoothly without chattering along the center axis of thetransparent cover 313, that is, the center axis of the outer shell.

In the inner peripheral surface of the tube-shaped part 415, aninternal-tooth gear 415 a is formed. The gear teeth of theinternal-tooth gear 415 a extend in parallel to the center axis of thetube-shaped part 415, and are formed at equal intervals in thecircumferential direction. Further, in the outer peripheral surface ofthe tube-shaped part 415, a male screw 415 b is formed that is screwedinto the thread groove formed in the inner peripheral surface of thebody part 11.

In the objective lens mount part 414, a cylindrical hole 414 a is formedthat is continuous to the tip opening of the tube-shaped part 415 andextends in the axial direction of the tube-shaped part 415. Then, anobjective mirror 16 is accommodated in the cylindrical hole 414 a.Further, in the objective lens mount part 414, an image pick-up hole 414b is formed that extends in a radial direction and whose one end opensin the outer peripheral surface and whose the other end faces thereflecting surface of the objective mirror 16 in a radial direction andcommunicates with the cylindrical hole 414 a. Then, an objective lens 17is mounted in the opening part on the outer periphery side of the imagepick-up hole 414 b.

Object light is focused along the cylindrical part 313 c of thetransparent cover 313 by the objective lens 17 so as to travel to theobjective mirror 16 in the form of a parallel light beam. Then, theobject light is reflected by the reflecting surface of the objectivemirror 16, and then travels along the center axis of the tube-shapedpart 415 in parallel to the center axis of the outer shell, withmaintaining the form of a parallel light beam.

In the inside of the body part 11, an image pick-up drive unit part 37is arranged at a position located on an extended line of the center axisof the tube-shaped part 415 of the lens holder 419. The image pick-updrive unit part 37 is the same as that of the electronic endoscope 1described above. Thus, description is omitted.

Here, in the lens holder 419 whose tube-shaped part 415 is screwed intothe thread groove formed in the inner peripheral surface of the bodypart 11, movement is guided along the center axis of the body part 11,that is, along the center axis of the outer shell. The driving section421 for moving the lens holder 419 along the center axis of the outershell is described below in detail with reference to FIG. 30.

A stepping motor 61 is fixed inside the body part 11. Further, an idlegear wheel 65 is provided that is located between and engaging with bothof the motor gear wheel 63 of the stepping motor 61 and theinternal-tooth gear 415 a formed in the tube-shaped part 415 of the lensholder 419. The revolution of the stepping motor 61 is transmittedthrough the motor gear wheel 63 and the idle gear wheel 65 to the lensholder 419.

In the lens holder 419, the tube-shaped part 415 is fit into the bodypart 11. Thus, when revolution of the stepping motor 61 is transmitted,the lens holder 419 revolves about the center axis of the body part 11.At the same time, the tube-shaped part 415 is screwed into the threadgroove formed in the inner peripheral surface of the body part 11 bymeans of the male screw 415 b formed in the outer peripheral surface.Thus, in association with revolution about the center axis of the bodypart 11, the lens holder 419 moves along the center axis of the bodypart 11.

For example, in a situation that the lens holder 419 is located at araised position shown in FIG. 32, the stepping motor 61 is revolved in apredetermined direction so that the lens holder 419 is revolved via themotor gear wheel 63 and the idle gear wheel 65. As a result, as shown inFIG. 33, the lens holder 419 revolves about the center axis of the bodypart 11 so as to go lower by Δh along the center axis of the body part11. In accordance with the revolution of the lens holder 419, theobjective lens 17 is also revolved so that the field of view of imagepick-up moves in the circumferential direction.

The operation of the electronic endoscope 401 is similar to that of theelectronic endoscope 301 described above. That is, the driving section421 causes the lens holder 419 that holds the objective lens 17 to movein the axial and the circumferential directions sequentially. Then, inthe course of this motion, image pick-up is performed in the entiredirections.

According to the electronic endoscope 401, in the guiding of themovement of the lens holder 419, the inner peripheral surface of thebody part 11 is used in place of the feed screw 367 of the electronicendoscope 301 described above. This reduces the number of componentsand, at the same time, permits such a configuration that the imagepick-up drive unit part 37 and the like are accommodated inside thetube-shaped part 415 guided by the inner peripheral surface of the bodypart 11. Accordingly, efficient space utilization is achieved and sizereduction of the electronic endoscope is realized.

As described above with reference to the electronic endoscopes 1, 101,201, 301, and 401 serving as examples, the present specification hasdisclosed an electronic endoscope characterized in that an outer shellthat is formed in a tube shape and whose peripheral wall is providedwith a transparent window part extending in an axial direction; asolid-state imaging device that is provided inside the outer shell; anobjective optical system that includes an objective lens for focusingobject light through the window part and that forms an image onto thesolid-state imaging device; and a drive mechanism that causes at leastthe objective lens in the objective optical system to move along an axisof the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the drive mechanism includes a lens holder forsupporting the objective lens, a feed screw extending along the axis ofthe outer shell, and a motor for driving and revolving the feed screw,and wherein the lens holder engages with a thread groove of the feedscrew and revolution about the feed screw as an axis of revolution isrestricted.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the drive mechanism includes a lens holder forsupporting the objective lens, a feed screw extending along the axis ofthe outer shell, and a motor for driving and revolving the lens holderabout the feed screw as an axis of revolution, and wherein the lensholder engages with a thread groove of the feed screw.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the outer shell is formed in a cylindrical shapeand a thread groove is formed in its inner peripheral surface, whereinthe driving section includes a lens holder for supporting the objectivelens and a motor for driving and revolving the lens holder about theaxis of the outer shell as an axis of revolution, and wherein the lensholder engages with the thread groove of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized by comprising a control section that reads an imagepick-up signal from the solid-state imaging device and that generatesimage data, and a memory that stoles the image data are further includedin the outer shell.

The electronic endoscope 500 shown in FIGS. 34 to 36 comprises: a bodypart 511 and a transparent cover 513 serving as an outer shell; a lensholder 519 that is accommodated inside the body part 511 and that isprovided with an objective lens group 517 serving as a wide-angle lensarranged on one-end side of the tube-shaped part 515; a raising andlowering driving section 521 for moving the lens holder 519 in theinside of the transparent cover 513 and the body part 511 in the opticalaxis direction of the objective lens group 517; and a solid-stateimaging device 523 that receives the object light acquired through theobjective lens group 517 and then converts the light into an electricsignal.

The body part 511 is formed in a closed-bottom cylindrical shapefabricated from resin material or the like having light shieldingproperty. Its bottom part (lower side in FIG. 35) 511 a is provided witha tube-shaped battery accommodating part 511 b. After a power battery525 is mounted, the battery accommodating part 511 b is airtightlyclosed by a battery lid 527. That is, the power battery 525 is built inthe body part 511 so that the necessity of power supply from the outsideis avoided. This avoids the necessity of connection of a power supplycable to the body part, and hence enhances the easy handling of theelectronic endoscope 500 itself. Here, the shape of the body part 511 isnot limited to a cylinder, and may be a tube of another kind, a hollowshape, or the like.

Further, in the bottom part 511 a, in the example shown in the figure,two hard wiring protection tubes 529 fabricated from resin are fixed ina protruding manner toward the outside. Then, wiring for outputting animage signal or the like is allowed to be inserted through the wiringprotection tubes 529. Here, at the time of use of the electronicendoscope 500, the wiring protection tubes 529 serve also as grip pipesused for inserting or extracting the entirety of the electronicendoscope 500 into or from a hole or an abdominal cavity serving as asubject.

In the inner peripheral surface of the body part 511, ribs 531 extendingin the longitudinal direction of the body part 511 are formed and engagewith engagement groove 535 formed in the flange 533 of the lens holder519, so that revolution of the lens holder 519 is stopped.

The transparent cover 513 is formed from hard transparent resin. Theapex part on the tip side is formed in a smooth hemispherical shape thatpermits easy insertion into the inside of a subject. An open end part513 b that is located on the side opposite to the hemispherical part 513a and has an expanded diameter and an open end part 511 c of the bodypart 511 are aligned to each other and fixed by bonding. The transparentcover 513 may be fabricated by integral molding, or alternatively byjoining the hemispherical part 513 a and the open end part 511 c bybonding. Further, light shielding property may be imparted to thehemispherical part 513 a so that it may be prevented that external lightis introduced directly into the objective lens group 517. Here, it issufficient that the transparent resin is transparent to light at aparticular wavelength. That is, the material need not be transparent tovisible light.

The hemispherical part 513 a of the transparent cover 513 and thecylindrical part 513 c extending from the hemispherical part 513 a tothe open end part 513 b have a smaller diameter than the open end part513 b that has almost the saner diameter as the external shape of thebody part 511. As such, since the hemispherical part 513 a and thecylindrical part 513 c are formed in a smaller diameter, they are easilyinserted into a narrow inside of a subject This expands the range ofapplication of the electronic endoscope 500. Here, the cylindrical part513 c of the transparent cover 513 may be in the form of afrontward-tapered shape. In this case, the tip of the transparent cover513 is easily inserted into a small hole or a small abdominal cavity.Further, the hemispherical part 513 a and the cylindrical part 513 c maybe formed in a diameter that is equal to the external shape of the bodypart 511 and that is the same as the open end part 513 b. In this case,no tapered tip is formed. Thus, the strength of the electronic endoscope500 is improved and its robustness is improved.

The lens holder 519 is fabricated from resin material or the like andformed in an outer surface shape that follows the inner surface of thetransparent cover 513. The objective lens group (a wide-angle lens 517Aand a lens 517B) is fixed to one-end side of the tube-shaped part 515 soas to close the opening of the one-end side apex part. Preferably, thewide-angle lens 517A is composed of a fish-eye lens. In this case, acircular fish-eye lens is suitable for observation in the entirecircumferential directions where the inclination angle (angle relativeto the lens optical axis) is large. That is, the wide-angle lens is awide-angle lens having an observational field of view that permitsobservation in the entire side circumferential directions around theoptical axis (the center axis of the tube-shaped part 515) of theobjective lens group 517. Here, in addition to this configuration, thewide-angle lens 517A may be composed of a diagonal fish-eye lens, acommon wide-angle lens, or the like. The optical axis of the objectivelens group 517 fixed to the lens holder 519 agrees with the center axisdirection of the tube-shaped part 515 of the lens holder 519. Then, inthe tube-shaped part 515 of the lens holder 519, its outer diameter isformed somewhat smaller than the inner diameter of the cylindrical part513 c of the transparent cover 513. Thus, the tube-shaped part 515 isallowed to move inside the transparent cover 513 smoothly withoutchattering.

At a position on an extended line of the center axis of the cylindricalpart 513 c extended toward the bottom part 511 a of the body part 511,an image pick-up drive unit part 537 is arranged. The image pick-updrive unit part 537 is mounted and fixed in the inside of the body part511 by using a stay member (not shown) in a state that the peripheralwall of the battery accommodating part 511 b provided in the bottom part511 a of the body part 511 serves as a supporting column. In the exampleshown in the figure, the image pick-up drive unit part 537 has threebase plates 541, 542 and 543.

FIG. 37 shows an enlarged perspective view of a part containing theimage pick-up drive unit part 537. The base plate 541 in the lowermostlayer (on the bottom part 511 a side) is provided with a control unit545 containing a driver circuit for the stepping motor and othercircuits. The middle layer the base plate 542 is provided with an imagememory 547 for storing pick-up image data. The upper layer base plate543 is provided with an imaging device 523 composed of a solid-stateimaging device such as a CCD type imaging device and a CMOS type imagingdevice.

In the center part of the base plate 543 containing the center axis ofthe cylindrical part 513 c, a focusing lens holder 549 formed in acylindrical shape is arranged. Then, the focusing lens holder 549accommodates the imaging device 523 in the inside. Then, a focusing lens551 is arranged in the upper-end opening part of the focusing lensholder 549. Thus, the parallel light beam (object light) L1 guided alongthe center axis is focused onto the light acceptance surface of theimaging device 523 by the focusing lens 551 so that an image is formed.

Further, a half mirror 553 is arranged in the middle of the optical pathbetween the objective lens group 517 and the imaging device 523. Then,emitted light from a light emitting diode (LED) 555 serving as a lightemitting body is directed to the objective lens group 517 by reflectionin the half mirror 553, and then projected as light for illumination L2.That is, the half mirror 553 is arranged at a position in the immediateupstream of the focusing lens 551 within the parallel light beamentering the focusing lens 551 in a state that the half mirror 553 isinclined by 45 degrees relative to the optical axis of the parallellight beam (the center axis of the cylindrical part 513 c). Then, anillumination lens 557 for deflecting the light for illumination into theform of a parallel light beam toward the half mirror 553 is providedbetween the LED 555 and the half mirror 553. The half mirror 553, theillumination lens 557, and the LED 555 are fixed inside the body part511 individually by appropriate support members.

Here, as shown in FIGS. 38A and 38B, the tube-shaped part 515 of thelens holder 519 provided with the objective lens group 517 is allowed tomove in the inside of the transparent cover 513 and the body part 511 inthe optical axis direction of the objective lens group 517 (the centeraxis direction of the tube-shaped part 515). That is, the position ofthe wide-angle lens 517A can be set up arbitrarily between height h1shown in FIG. 38A and height hn shown in FIG. 38B.

Means for moving the lens holder 519 is described below in detail withreference to FIGS. 35, 39A, and 39B. A motor holding member (not shown)is provided in the inside of the body part 511. Then, the stepping motor561 is attached to this motor holding member. The shaft of the steppingmotor 561 is in parallel to the center axis of the tube-shaped part 515(the optical axis of the parallel light beam). A motor gear wheel (spurwheel) 563 is attached to the shaft of the stepping motor 561. Then, themotor gear wheel 563 engages with an idle gear wheel 565 composed of aspur wheel. Then, the idle gear wheel 565 engages with a gear wheel 569fixed to one-end side of the feed screw 567 by press fit or bonding.Thus, the revolving force of the stepping motor 561 is transmittedthrough the motor gear wheel 563, the idle gear wheel 565, and the gearwheel 569 to the feed screw 567. Here, the idle gear wheel 565 has alarger number of gear teeth than the motor gear wheel 563. Thus, therevolution speed of the stepping motor 561 is reduced and thentransmitted to the idle gear wheel 565. Here, the stepping motor 561 fordriving the feed screw 567 is not limited to a motor operated by pulsedrive, and may be a motor of a diverse kind such as a servo motorprovided with an encoder, or alternatively may be a power source ofanother type.

As shown in the sectional part view of FIG. 40, in the feed screw 567,the tip on one-end side is inserted into the shaft hole 513 d formed inthe flange face of the open end part 513 b of the transparent cover 513.Further, the-other-end side of the feed screw 567 is supported in arevolvable manner by the support arm 571 provided in the side face ofthe focusing lens holder 549 of the image pick-up drive unit part 537.Thus, the feed screw 567 driven and revolved by the revolution of thestepping motor 561. Here, the stepping motor 561, the motor gear wheel563, the idle gear wheel 565, and the gear wheel 569 stay at the sameheight position inside the body part 511 regardless of the movement ofthe lens holder 519.

On the other hand, the flange 533 of the lens holder 519 is providedwith an opening 573 for avoiding interference with the motor gear wheel563, the idle gear wheel 565, the gear wheel 569, and the like at araised position of the lens holder 519 shown in FIG. 39A. Then, a feednut 575 screwed onto the feed screw 567 is fixed to the flange 533 by anut holding piece 577.

According to the above-mentioned configuration, the feed screw 567 andthe lens holder 519 provided with the feed nut 575 serve as a linearmovement mechanism for moving the lens holder 519 in the axial directionof the feed screw 567 in association with the revolution operation ofthe feed screw 567.

For example, when the stepping motor 561 is driven starting from theraised position of the lens holder 519 shown in FIG. 39A, the feed screw567 is driven and revolved via the motor gear wheel 563, the idle gearwheel 565, and the gear wheel 569. When the feed screw 567 is driven andrevolved, the feed nut 575 screwed onto this is moved relative to thefeed screw 567. As a result, as shown in FIG. 39B, the lens holder 519is lowered down from the raised position.

FIG. 41 is a functional block diagram showing the image pick-up driveunit part 537. The control section (CPU) 581 for collectivelycontrolling the entire system is connected to: a memory 583 that storesa control program and serves also as a work memory and that contains theimage memory 547 provided on the base plate 542 described in FIG. 37; anLED drive circuit 585 for driving the LED 555; an imaging device driver587 for driving the imaging device 523; and a pulse generator 591 forproviding driving pulses to the motor driver 589 for driving thestepping motor 561. Image data obtained by image processing in thecontrol section 581 is stored into the image memory 547 built in thebody part 511. This permits acquisition of an image by the electronicendoscope 500 in a stand alone mode. Thus, easy handling is enhanced.

Further, the electronic endoscope 500 has a power switch 593. When thepower switch 593 is turned ON, electric power from the power battery 525is supplied through wiring (not shown) to the individual parts of theimage pick-up drive unit part 537, so that image pick-up operation anddrive operation are performed as described later.

For example, the power switch 593 may be provided in the bottom part 511a of the body part 511, and may be turned ON or OFF by manual operation.Alternatively, a switch terminal that follows magnetism may be built inthe body part 511. Then, from the outside of the electronic endoscope500, a magnet may be brought close or apart so that the switch terminalmay be turned ON or OFF.

Next, the operation of the electronic endoscope 500 is described below.As shown in FIGS. 35 and 41, when the power switch 593 is turned ON,electric power is supplied from the power battery 525 to the individualparts so that their operation is started and hence the stepping motor561 is driven and revolved. Thus, the lens holder 519 moves in theinside of the electronic endoscope 500 in the center axis direction ofthe tube-shaped part 515, and then stops at a home position (forexample, a raised-end position of the lens holder 519). Further; emittedlight from the LED 555 is brought into the form of a parallel light beamby the illumination lens 557. Then, the parallel light beam is reflectedto the direction of the objective lens group 517 by the half mirror 553,and then projected through the objective lens group 517 over the entirecircumference of the directions (the side face directions relative tothe direction of insertion into the subject) that are approximatelyperpendicular to the center axis of the tube-shaped part 515. As such,the light serves as light for illumination.

The reflected light from the image-taking object is acquired through theobjective lens group 517 into the electronic endoscope 500. Then, theoptical image of the image-taking object travels to the focusing lens551 in the form of a parallel light beam. And then, an image is formedonto the light acceptance surface of the imaging device 523 by thefocusing lens 551. FIG. 42 shows the situation of the view field regionW formed by the objective lens group 517. The light for illuminationemitted from the wide-angle lens 517A is projected onto the regionindicated as the view field region W. Among the reflected light from theimage-taking object illuminated by the light for illumination, the partof light belonging to the view field region W is used in image formationand then acquired by the imaging device 523. Here, in the center part ofthe optical axis of the wide-angle lens 517A, a light shielding mask Mfor defining the upper end of the view field region W is provided. Inthis example, a light shielding mask M having a circular shape whoseradius is set up in correspondence to the view field region W isprovided in the outer surface (the surface on the light exit side) ofthe wide-angle lens 517A.

The image pick-up signal of the image-taking object acquired by theimaging device 523 is inputted to the control section (CPU) 581 and thenundergoes image processing. Then, the obtained data, for example, in theform of PEG image data is stored into the memory 583 (the image memory547).

FIG. 43 is a flow chart showing the processing procedure of a controlprogram stored in the memory 583. When the power switch 593 is turnedON, this control program is invoked. Then, first, the stepping motor 561is driven so that the lens holder 519 is moved toward the home position(the raised end position) (S1). The home position is defined, forexample, as a position where the objective lens group 517 is located onthe tip side of the electronic endoscope 500 as shown in FIGS. 34 and38A. However, the definition is not limited to this, and may be theposition on the pedestal side opposite to the tip side (the position ofthe lens holder shown in FIG. 38B).

After the lens holder 519 reaches the home position, image pick-upprocessing is performed (S2). The image pick-up processing includes:processing that the LED 555 is turned ON so that light for illuminationis projected through the objective lens group 517, and then lightreflected from the image-taking object is acquired through the objectivelens group 517 into the electronic endoscope 500 so that an image isformed onto the light acceptance surface of the imaging device 523; andprocessing that the imaging device 523 generates an image pick-upsignal, then the image pick-up signal of the image-taking objectundergoes image processing, and then the obtained data is stored intothe memory 583 (the image memory 547).

Then, the stepping motor 561 is driven by a specified number of pulses(S3), so that the lens holder 519 is lowered by a predetermineddistance. The predetermined distance indicates a step distance by whichthe lens holder 519 is to be moved stepwise in order that the view fieldregion W shown in FIG. 42 should cover stepwise the movable region ofthe lens holder 519. For example, the predetermined distance may be theheight La of a part contained in the view field region W in thecylindrical part 513 c of the transparent cover 513.

Until the destination reaches the most lowered position of the lensholder 519 (S4), image pick-up processing is performed at eachdestination of the movement (S2). Then, S2 and S3 are repeated so thatan image map as shown in FIG. 44 is generated by combining the pick-upimages obtained by individual occasions of image pick-up (S5). That is,the pick-up image data IMG(1) of the first occasion is image data of theview field region W1 over the entire circumferential directions(circumferential angle from 0 degree to 360 degrees) in a situation thatthe wide-angle lens 517A of the objective lens group 517 is located atheight h1 shown in FIG. 38A. The pick-up image data IMG(2) of the secondoccasion is image data of the view field region W2 over the entirecircumferential directions in a situation that the wide-angle lens 517Ahas been lowered down together with the lens holder 519 from theposition of height h1 by a predetermined distance and hence is locatedat height h2. As such, plural sheets of image data IMG(1) to IMG(n) eachobtained at each position of the movement of the lens holder 519 arecombined into a substantially single sheet of image data (image map) bylinking the data pieces with each other in the height direction. Here,in a configuration that a part of the view field region of an imagetaking occasion overlaps with the view field region of the next imagetaking occasion, even junction regions of the images are acquiredwithout a missing part. This provides image data without a gap.

After the image map is generated from the above-mentioned pick-up imagedata IMG(1) to IMG(n), the accumulated data is read to the outside fromthe memory 583 (see FIG. 41) storing the image map. This read operationmay be performed by wireless, or alternatively by using a wiringinserted through the wiring protection tubes 529 shown in FIG. 34.Alternatively, the memory 583 may be provided in a removable manner fromthe electronic endoscope 500. Then, the removed memory 583 may be readby a personal computer provided separately.

Further, the electronic endoscope 500 may transmit the pick-up imagedata to an external monitor, so that the pick-up image may be observedon line through the external monitor. In addition, operationinstructions may be inputted from the outside. In this case, withoutperforming image processing, the control section 581 transmits the imagepick-up signal acquired from the imaging device 523, to an externalvideo processor in an intact manner. Then, an object image obtained byimage processing by the video processor is displayed on the externalmonitor. The communication between the external video processor, theexternal monitor, and the control section 581 may be of cable orwireless. In a case that the communication is of cable, an externalpower source becomes employable when a power source line is included inthe wiring.

Further, as another example of the control program, a control programmay be employed that, in addition to the control procedure shown in theflow chart of FIG. 43, allows the view field region of the objectivelens group 517 to be moved to an arbitrary position in accordance withan operation instruction from the outside. In this case, selective imagepick-up of a desired site is achieved in accordance with the purpose ofimage pick-up, and hence more detailed observation of the site isallowed.

As described above with reference to the electronic endoscope 500serving as an example, the present specification has disclosed anelectronic endoscope that is inserted into a subject and then acquiresan image inside the subject, characterized in that a lens holder thathas a tube-shaped part; a wide-angle lens that is mounted on the lensholder and that is arranged on one-end side of the tube-shaped part in astate that an optical axis is aligned to a center axis of thetube-shaped part so that an observational field of view extends to asideward region of the tube-shaped part an imaging device that receiveslight acquired through the wide-angle lens and that converts the lightinto an electric signal, a transparent cover that covers one-end side ofthe tube-shaped part and at least whose part facing the observationalfield of view of the wide-angle lens has transparency; a tube-shapedbody part that is connected to the transparent cover on the-other-endside of the tube-shaped part; and a driving section that is arrangedinside the body part and that causes the lens holder to advance orretreat in the center axis direction.

According to this electronic endoscope, the lens holder inside thetransparent cover advances or retreats by virtue of the driving section.This permits image pick-up at different positions along the center axisof the tube-shaped part of the lens holder, and hence image informationto be acquired through the wide-angle lens is allowed to be acquiredaccurately within the moving range of the lens holder. Thus, without thenecessity of moving the electronic endoscope within the subject, acontinuous image of a large region is acquired easily.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the imaging device receives light from an entiresideward circumference of a direction of insertion into the subject.

According to this electronic endoscope, image information for the entiresideward circumference of the direction of insertion into the subject isacquired, and then the image information is combined to each other sothat a single sheet of entire sideward circumferential image isgenerated easily.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the wide-angle lens is composed of a circularfish-eye lens.

According to this electronic endoscope, since the circular fish-eye lensis employed, an image of the entire sideward circumference of theoptical axis of the wide-angle lens is obtained efficiently. Further,this permits image pick-up from a direction almost perpendicular to theobservation surface of the subject.

Further, the present specification has disclosed an electronic endoscopecharacterized by comprising: a half mirror that is arranged in thecourse of the optical path between the wide-angle lens and the imagingdevice; and a light emitting body that emits light for illumination tobe projected through the wide-angle lens after reflection by the halfmirror and thereby illuminates the subject.

According to this electronic endoscope, the emitted light from the lightemitting body is reflected toward the subject by the half mirror. Then,this reflected light serves as light for illumination that illuminatesthe entire sideward circumference of the subject.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the tube-shaped part of the lens holder and a tippart of the transparent cover that covers the tube-shaped part areformed in a smaller diameter than the body part.

According to this electronic endoscope, image information is acquired bythe tip part having a smaller diameter than the body part. This permitseasy insertion even into a narrow region of the subject and hence easyobservation of the inside of the subject. This expands the range ofapplication of the electronic endoscope.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the driving section includes: a feed screw whichis supported inside the body part in a revolvable manner in parallel tothe optical axis direction of the wide-angle lens, a feed nut which isfixed to the lens holder in a screwed manner onto the feed screw, and amotor which drives and revolves the feed screw.

According to this electronic endoscope, the feed screw is revolved bythe motor so that the feed nut screwed onto the feed screw is moved inthe axial direction of the feed screw. By virtue of this, the lensholder is advanced or retreated in parallel to the optical axisdirection of the wide-angle lens.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a control section that performs image processingon an image signal obtained by image pick-up performed by the imagingdevice and an image memory that stores image data obtained by imageprocessing performed by the control section are included in the insideof the body part.

According to this electronic endoscope, image data obtained by imageprocessing in the control section is stored into the image memory builtin the body part. This permits acquisition of an image by the electronicendoscope in a stand alone mode. Thus, easy handling is enhanced.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a power battery for supplying electric power tothe imaging device and the driving section is built inside the bodypart.

According to this electronic endoscope, the power battery is built inthe body part. This avoids the necessity of power supply from theoutside, and hence avoids the necessity of a power supply cableconnected from the outside of the body part. Thus, easy handling isenhanced.

The electronic endoscope 601 shown in FIG. 45 is of side-viewing typeand, at the same time, of hard type. The electronic endoscope 601 isconstructed from: a body part 602 and a transparent capsule (transparentcover) 603 serving as an outer shell; and a moving lens frame section(lens holder) 604 accommodated inside and an image pick-up drive unitpart 605 described later.

FIG. 46 is an exploded perspective view of the electronic endoscope 601.FIG. 47 is a longitudinal sectional view of the electronic endoscope601.

The body part 602 is formed in a closed-bottom cylindrical shape byusing resin material or the like. Then, a tube-shaped batteryaccommodating part 602 b is provided in its bottom part (lower side inFIG. 46) 602 a. Then, after a power battery 611 is mounted, the batteryaccommodating part 602 b is closed airtightly by a battery lid 612. Thatis, the electronic endoscope 601 is provided with the power battery 611in the inside, and hence does not require other power supply from theoutside. Thus, the electronic endoscope 601 need not be connected to apower supply cable, and hence permits easy handling.

Further, in the bottom part 602 a, in the example shown in the figure,two hard grip pipes 613 and 614 fabricated from resin are fixed in aprotruding manner toward the outside. Then, when the grip pipes 613 and614 are manipulated by hand, the entirety of the electronic endoscope601 is inserted into or extracted from a hole or an abdominal cavityserving as a subject. The electronic endoscope 601 may be used in aconfiguration that wiring is inserted through the grip pipes 613 and614.

In the inner peripheral surface of the body part 602, a precision femalescrew 602 c is engraved about the axis of the body part 602. Then, themoving lens frame section 604 provided with a male screw is screwed inand revolved so that the member 604 advances or retreats in the axialdirection.

The transparent capsule 603 is formed in the form of a tube bodyfabricated from hard transparent resin. Its one-end side (tip side) isformed hemispherical. Then, the open end part 603 b on the side oppositeto the hemispherical part 603 a is bonded and fixed to the open end part602 d of the body part 602 in an aligned orientation. In the exampleshown in the figure, the entirety of the capsule section 603 is formedfrom transparent resin. However, it is sufficient that at least the partof the cylindrical part 603 c serving as an observation window istransparent. The hemispherical part 603 a may be opaque. The observationwindow indicates the part faced by a later-described objective lens 617in association with revolution of the moving lens frame section.Further, in place of a configuration that the hemispherical part 603 aand the cylindrical part 603 c are formed integrally from the samematerial, they may be formed as separate members and then joined andintegrated. Here, it is sufficient that the transparent resin istransparent to light at particular wavelengths such as infrared light.That is, the material need not be transparent to visible light.

Such a configuration may be employed that the hemispherical part 603 ais formed in a yet smaller diameter than that shown in the figure andthat the tip part of the cylindrical part 603 c of the transparentcapsule 603 is reduced into a tapered shape and then connectedcontinuously and smoothly to the hemispherical part 603 a. According tothis configuration, the tip part of the transparent capsule 603 iseasily inserted even into a smaller hole or a smaller abdominal cavity.Here, the outer diameter of the cylindrical part 603 c of thetransparent capsule 603 and the outer diameter of the body part 602 arecompletely identical. Thus, no level difference occurs between these.

The moving lens frame section 604 includes: an objective lens mount part604 a formed in a disk shape by using resin material; and a cylindricalmember 604 b having almost the same diameter as the objective lens mountpart 604 a. Then, the objective lens mount part 604 a is bonded andfixed integrally at the upper open end part (in the direction to the tipof the electronic endoscope 601) of the cylindrical member 604 b, sothat the open end part is closed. The outer diameter of the objectivelens mount part 604 a is formed somewhat smaller than the inner diameterof the transparent capsule 603. This allows the objective lens mountpart 604 a to move inside the transparent capsule 603 smoothly withoutchattering.

In the outer peripheral surface of the cylindrical member 604 b, aprecision male screw 604 c screwed into the female screw 602 c engravedin the inner peripheral surface of the body part 602 is engraved overthe entire length in the axial direction of the cylindrical member 604b. Further; an internal-tooth gear 604 d is formed in the innerperipheral surface of the cylindrical member 604 b. The internal-toothgear 604 d is formed such that gear teeth parallel to the axis andextending over the entire length in the axial direction of thecylindrical member 604 b are arranged at equal intervals in thecircumferential direction.

In the center axis part of the objective lens mount part 604 a, acylindrical hole 604 e is formed that has a bottom part in the upper enddirection (the direction of the tip of the electronic endoscope 601).Then, an objective mirror 616 is accommodated in the cylindrical hole604 e. The objective mirror 616 has a shape obtained by cutting acylindrical glass material obliquely at 45 degrees. Then, a reflectionfilm is formed on the obliquely cut surface at 45 degrees.

In the objective lens mount part 604 a, an image pick-up hole 604 f forimage pick-up is formed that extends straight in a radial direction ofthe disk-shaped member. Then, one-end of the image pick-up hole 604 f isopen in the peripheral side face of the objective lens mount part 604 a,and then an objective lens 617 composed of a concave lens is provided inthis opening part. The other end of the image pick-up hole 604 f is opentoward the cylindrical hole 604 e. Thus, the object light having enteredthe image pick-up hole 604 f through the objective lens 617 travels inthe form of a parallel light beam, then is reflected by theabove-mentioned 45-degree-oblique reflecting surface of the objectivemirror 616, and then travels along the center axis of the cylindricalmember 604 b in the form of a parallel light beam.

Here, in FIG. 47, in order that the inside of the image pick-up hole 604f and the above-mentioned parallel light beam should be seen clearly,illustration is omitted for the gear teeth of the internal-tooth gear604 d which are to be seen on the far side of the parallel light beam.Then, the parallel light beam is shown as a white part.

The image pick-up drive unit part 605 is mounted and fixed in the insideof the body part 602 by using a stay member (not shown) in a state thatthe peripheral wall of the battery accommodating part 602 b provided inthe bottom part 602 a of the body part 602 serves as a supportingcolumn. In the example shown in the figure, the image pick-up drive unitpart 605 has three base plates 621, 622, and 623.

The base plate 621 in the lowermost layer (on the bottom part 602 aside) is provided with a control unit 625 containing a driver circuitfor the stepping motor and other circuits. The middle layer the baseplate 622 is provided with an image memory 626 for storing pick-up imagedata. The upper layer base plate 623 is provided with a solid-stateimaging device 627 such as a CCD type imaging device and a CMOS typeimaging device and a stepping motor 628.

In the center part of the base plate 623, a lens holder 629 formed in acylindrical shape is provided. Then, the solid-state imaging device 627is accommodated in the inside. Then, a focusing lens 630 is mounted inthe upper-end opening part of the lens holder 629. Then, theabove-mentioned parallel light beam (object light) entering along thecenter axis is focused onto the light acceptance surface of thesolid-state imaging device 627 by the focusing lens 630 so that an imageis formed.

Further, with reference to FIG. 48, in a part in the immediate upstreamof the focusing lens 630 within the parallel light beam entering thefocusing lens 630, a half mirror 631 is provided that is arrangedoblique to the optical axis of the parallel light beam (the center axisof the cylindrical member 604 b). In the example shown in the figure,the reflecting surface of the half mirror 631 is inclined at 45 degreesrelative to the optical axis of the parallel light beam. However; theinclination angle may be arbitrary as long as the reflecting surfacedoes not intersect the optical axis at right angles. The half mirror 631is an optical member that allows a part of the incident light totransmit through and that reflects the remaining part of the incidentlight. The ratio of transmission and reflection may be set upappropriately. Further provided are: an LED 633 for emitting light forillumination toward the half mirror 631; and an illumination lens 632that intervenes between the half mirror 631 and the LED 633 and thatprojects the light for illumination from the LED 633, toward the halfmirror 631 in the form of a parallel light beam. The half mirror 631,the illumination lens 632, and the LED 633 are fixed to the base plat623.

The stepping motor 628 is fixed in the periphery part of the base plate623. Then, a motor gear wheel (spur wheel) 636 is attached to the shaftof the stepping motor 628. The shaft of the stepping motor 628 isoriented in parallel to the center axis of the cylindrical member 604 b(the optical axis of the parallel light beam). Then, the motor gearwheel 636 engages with an idle gear wheel 637 composed of a spur wheel.

The shaft of the idle gear wheel 637 is pivotally supported in arevolvable manner in a direction perpendicular to the base plate 623.The idle gear wheel 637 has a larger number of gear teeth than the motorgear wheel 636. Thus, the revolution of the stepping motor 628 is sloweddown and then transmitted to the idle gear wheel 637. The idle gearwheel 637 engages with the internal-tooth gear 604 d provided in theinner peripheral surface of the cylindrical member 604 b.

When the stepping motor 628 revolves, the idle gear wheel 637 revolves.Then, in association with this, the cylindrical member 604 b revolves.When the cylindrical member 604 b revolves, the cylindrical member 604 bof the moving lens frame section 604 is screwed into or out from thebody part 602 depending on the direction of revolution. That is, themoving lens frame section 604 advances or retreats in the axialdirection.

Further, the electronic endoscope 601 has a power switch (not shown).When the power switch is turned ON, electric power from the powerbattery 611 is supplied through wiring (not shown) to the individualparts of the image pick-up drive unit part 605, so that image pick-upoperation and drive operation are performed as described later.

For example, the power switch may be provided in the bottom part 602 aof the body part 602, and may be turned ON or OFF by manual operation.Alternatively, a switch terminal that follows magnetism may be built inthe body part 602. Then, from the outside of the electronic endoscope601, a magnet may be brought close or apart so that the switch terminalmay be turned ON or OFF.

FIG. 49 is a functional block diagram showing the image pick-up driveunit part 605. The CPU 641 for collectively controlling the entiresystem is connected to: a control memory 642 that stores a controlprogram and serves also as a work memory; an image memory 626 providedon the base plate 622 described in FIG. 47; an LED drive circuit 643 fordriving the LED 633; an imaging device driver 644 for driving theimaging device 627; and a pulse generator 646 for providing drivingpulses to the motor driver 645 for driving the stepping motor 628.

When the power switch 647 is turned ON, electric power is supplied fromthe power battery 611 to the individual parts so that operation isstarted. Thus, the stepping motor 628 is driven and revolved.Accordingly, the moving lens frame section 604 is revolved in the insideof the electronic endoscope 601 so as to advance or retreat in the axialdirection.

With reference to FIGS. 47 and 48, the light for illumination from theLED 633 is brought into the form of a parallel light beam by theillumination lens 632, then enters the half mirror 631, and then isreflected toward the objective mirror 616. The light for illuminationhaving entered the objective mirror 616 is reflected toward theobjective lens 617 with maintaining the form of a parallel light beam.Then, the light for illumination having entered the objective lens 617is projected through the objective lens 617 toward the image-takingobject, so as to serve as light for illumination that illuminates theimage-taking object contained in the view field region of the objectivelens 617. That is, the illumination lens 632, the half mirror 631, theobjective mirror 616, and the objective lens 617 constitute anillumination optical system.

The light for illumination is reflected by the image-taking object.Then, a part of the reflected light serving as object light enters theobjective lens 617. The object light having entered the objective lens617 is brought into the form of a parallel light beam, then travels tothe objective mirror 616, then is reflected by the objective mirror 616,then transmitting through the half mirror 631 with maintaining the formof a parallel light beam, and then travels to the focusing lens 630.Then, the object light is focused onto the light acceptance surface ofthe solid-state imaging device 627 by the focusing lens 630 so that animage is formed. That is, the objective lens 617, the objective mirror616, the half mirror 631, and the focusing lens 630 constitute anobjective optical system.

As such, the objective optical system and the illumination opticalsystem share the optical path of the interval between the half mirror631 and the objective lens 617. Thus, the light for illumination emittedfrom the LED 633 travels, in the reverse direction, the optical path ofthe object light in the objective optical system, then enters theobjective lens 617, and then projected toward the image-taking object.Thus, the image-taking object contained in the view field region of theobjective lens 617 is illuminated reliably.

Here, in the electronic endoscope 601, the LED 633 is arranged on thereflected light path of the object light reflected from the half mirror631, and the solid-state imaging device 627 is arranged on thetransmitted light path of the object light transmitted through the halfmirror 631. However, the employed configuration is not limited to this.That is, the LED 633 may be arranged on the transmitted light path, andthe solid-state imaging device 627 may be arranged on the reflectedlight path.

The image pick-up signal of the image-taking object acquired by theimaging device 627 is acquired into the CPU 641 so as to undergo imageprocessing, and then stored into the image memory 626, for example, inthe form of JPEG image data.

FIG. 50 is a flow chart showing the processing procedure of a controlprogram stored in the control memory 642. When the power switch 647 isturned ON, this control program is started. Then, first, the steppingmotor 628 is driven to the home position side (step S1). Here, the homeposition side indicates, for example, the state shown in FIG. 47 wherethe objective lens 617 is located on the tip side of the electronicendoscope 601.

In the electronic endoscope 601, for the purpose of cost reduction, asensor is not provided that detects whether the stepping motor 628 hasreached the home position. Thus, at the next step S2, it is judgedwhether a timer for counting a predetermined time has counted up. Then,when the predetermined time has not yet elapsed, step S1 is executedrepeatedly. In a configuration that a sensor for detecting reaching tothe home position is provided, step S1 is merely executed repeatedlyuntil reaching to the home position is detected by the sensor.

It is sufficient that the predetermined time is defined as the longesttime necessary for the stepping motor 628 to reach the home position.For example, the state shown in FIG. 52 is a state that the moving lensframe section 604 has revolved and moved to the lowermost position.Thus, the predetermined time may be defined as the time necessary fromthis state to a state that the moving lens frame section 604 hasrevolved in association with the revolution of the stepping motor 628 soas to have reached the home position (a position where the moving lensframe section 604 abuts against the inner peripheral surface of thehemispherical part 603 a and hence cannot move further in thisdirection) shown in FIG. 47.

By virtue of this, even in a case that the moving lens frame section 604is located wherever in the middle between the state shown in FIG. 47 andthe state shown in FIG. 52 (a state that the lower end of thecylindrical member 604 b abuts against the bottom part 602 a of the bodypart 602), the objective lens 617 necessarily reaches the home positionwhen the stepping motor 628 is driven in the home position direction bythe predetermined time.

When the timer has counted the predetermined time, the procedure goesfrom step S2 to step S3 where the contents of a counter described lateris cleared into zero. Then, the procedure goes to step S4 where imagepick-up processing is performed. In the image pick-up processing: theLED 633 is turned ON so that light for illumination is projected throughthe objective lens 617; light reflected from the image-taking object isacquired through the objective lens 617 into the electronic endoscope601; and then the incident light from the image-taking object is focusedonto the light acceptance surface of the imaging device 627 so that animage is formed.

Then, the CPU 641 drives the imaging device 627 via the imaging devicedriver 644 so as to acquire from the imaging device 627 the imagepick-up signal of the image-taking object obtained by the imaging device627, then performs image processing on the signal, and then stores thedata into the image memory 626.

At the next step S5, the stepping motor 628 is driven by a specifiednumber of pulses. At the next step S6, this specified number of pulsesis added to the count value in the counter. At the next step S7, thetotal count value in the counter is compared with a specified number.

Then, when the total count value in the counter does not reach thespecified number, the procedure returns from step S7 to step S4 so thatimage pick-up processing is performed. After that, the processing loopof steps S4 to S7 is executed repeatedly. When the total count value inthe counter has reached the specified number, the processing shown inFIG. 50 is terminated.

FIG. 53 is a diagram illustrating the movement of the field of view ofimage pick-up of the objective lens 617 in a case that step S4 in FIG.50 is executed repeatedly. In the first occasion of image pick-upprocessing performed at the home position, an object image in the fieldof view indicated by “No.001” in FIG. 53 is acquired from the imagingdevice 627.

After the image pick-up for the object image of the field of view“No.001”, the stepping motor 628 is driven at step S5 by a specifiednumber of pulses. Thus, the cylindrical member 604 b revolves by thespecified number of pulses. As a result, the cylindrical member 604 b isscrewed and withdrawn into the body part 602. Thus, the next field ofview is located at “No.002” in FIG. 53. Then, an object image in thisfield of view is taken, and then the obtained image data is accumulatedin the image memory 626.

After that, during the operation of moving the field of view likeNo.003→No.004→No.005 . . . , image pick-up processing and image dataaccumulation into the memory 626 are repeated. FIG. 51 shows a statethat the moving lens frame section 604 has gone half around inside thetransparent capsule 603 starting from the state shown in FIG. 47. Whenthe moving lens frame section 604 has gone one around from the homeposition inside the transparent capsule 603, the field of view of imagepick-up is located at No.011 in FIG. 53. In case of having gone aroundtwice, the field of view of image pick-up is located at No.021 in FIG.53.

Further, FIG. 52 shows a state that the lower end of the cylindricalmember 604 b abuts against the bottom part 602 a of the body part 602and hence cannot move further in this direction. When the state shown inFIG. 52 is reached, the processing loop of repeating the image pick-upprocessing (step S4) is terminated. Accordingly, the “specified number”used at step S7 in FIG. 50 is equal to the total number of pulsesnecessary for reaching from the home position to the state shown in FIG.52.

In the example of movement of the field of view of image pick-upillustrated in FIG. 53, the specified number of pulses at step S5 inFIG. 50 is set up such that in the direction of revolution of the movinglens frame section 604 serving as a lens holder, adjacent fields of viewof image pick-up are positioned such that their left and right edgeparts should be in contact with each other or overlapping somewhat witheach other. Further, the pitch of the screw threads provided in theinner peripheral surface of the body part 602 and the outer peripheralsurface of the cylindrical member 60413 is designed such that axiallyadjacent fields of view of image pick-ups are positioned such that theirupper and lower edge parts should be in contact with each other oroverlapping somewhat with each other.

By virtue of this, without a missing part over the entirety of thecylindrical field of view region of the inner peripheral surface of theimage-taking object serving as an observation object, image pick-up isachieved so that image data is acquired. Obviously, the number of pulsesfor the stepping motor may be set up, or alternatively the pitch of thescrews 602 c and 604 c may be designed such that larger overlappingparts should be generated in the fields of view of image pick-up.

Once image pick-up by the electronic endoscope 601 is completed, thedata accumulated in the image memory 626 shown in FIG. 49 is to be readto the outside. This read operation may be performed by wireless, oralternatively by using a wiring inserted through the grip pipes 613 and614 shown in FIG. 45. Alternatively, the image memory 626 may beprovided in a removable manner from the electronic endoscope 601. Then,the removed image memory 626 may be read by a personal computer providedseparately.

FIG. 54 is a functional block diagram showing a modification of theimage pick-up drive unit part 605. The only difference from the imagepick-up drive unit part 605 shown in FIG. 49 is that pick-up image datais transmitted to an external monitor so that the pick-up image isobserved on the external monitor on line and that an operationinstruction is allowed to be inputted from the outside.

In this case, without performing image processing, the CPU 641 transmitsthe image pick-up signal acquired from the imaging device 627, to anexternal video processor in an intact manner. Then, the object imageobtained by image processing in the video processor may be displayed onan external monitor. The communication between the external videoprocessor, the external monitor, and the CPU 641 may be of cable orwireless. In a case that the communication is of cable, an externalpower source becomes employable when a power source line is included inthe wiring.

Further, as a control program additional to the control program shown inFIG. 50, a control program is preferably installed that in accordancewith an operation instruction from the outside, for example, the viewfield position of the objective lens 617 it moved to an arbitrary imagepick-up view field position shown in FIG. 53.

Here, in the electronic endoscope 601 described above, the moving lensframe section 604 is driven and revolved by the stepping motor 628.However, obviously, in place of such a stepping motor, a motor of anytype may be employed as long as the revolution angle and the revolutionlength are controlled accurately.

As described above with reference to the electronic endoscope 601serving as an example, the present specification has disclosed anelectronic endoscope characterized in that: a cylindrical transparentcover at least whose observation window in a cylindrical part istransparent; a body part that has a cylindrical part providedcontinuously to the cylindrical part of the transparent cover; a lensholder that revolves about the center axis of the transparent cover inthe inside of the transparent cover and the body part and that moves inthe direction of the center axis; an objective mirror that is providedin the lens holder and that reflects, toward the body part, lightentering through an objective lens provided at a position facing thecylindrical part of the transparent cover; an imaging device thatreceives light reflected from the objective mirror and that converts thelight into an electric signal; and a driving section that is providedinside the body part and that drives and revolves the lens holder so asto drive the lens holder in the center axis direction.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the lens holder includes: a disk-shaped member onwhich the objective lens is mounted and the objective mirror is mounted;and a cylindrical member which is provided integrally and continuouslyto the body part side of the disk-shaped member.

Further, the present specification has disclosed an electronic endoscopecharacterized by comprising: a female screw which is formed spirally inthe inner peripheral surface of the body part; and a male screw that isengraved spirally in the outer peripheral surface of the cylindricalmember and engaging with the female screw and that, when the cylindricalmember is driven and revolved by the driving section, moves thecylindrical member in the center axis direction.

Further, the present specification has disclosed an electronic endoscopecharacterized in that an optical axis of the objective lens is providedin a direction perpendicular to an axis of revolution of the lensholder.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the objective mirror reflects light enteringthrough the objective lens, toward the body part along an optical pathgoing along the center axis.

Further, the present specification has disclosed an electronic endoscopecharacterized by comprising a half mirror that is provided in a courseof an optical path of light reflected from the objective mirror, and alight emitting body for emitting light for illumination, which is to bereflected by the half mirror and then reflected by the objective mirror,so as to illuminate a image-taking object through the objective lens.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a control section which performs image processingon an image signal obtained by image pick-up performed by the imagingdevice and an image memory which stores pick-up image data obtained byimage processing performed by the control section are built in.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a battery accommodating part which accommodates apower battery for supplying electric power to the imaging device and thedriving section is built in the body part.

An electronic endoscope 701 shown in FIGS. 55 to 57 includes: a bodypart 602 and a transparent capsule 603 serving as an outer shell; and amoving lens frame section 604 and an image pick-up drive unit part 605accommodated in the inside. Here, like members to those of theelectronic endoscope 601 described above are designated by likenumerals, and functionally common members are designated byappropriately corresponding numerals. Then, their description is omittedor simplified.

In the electronic endoscope 701, a hard grip plate 715 fabricated fromresin is bridged between the two grip pipes 613 and 614 fixed in andprotruding from the bottom part 602 a of the body part 602. The two grippipes 613 and 614 and the grip plate 715 constitute a manipulation partused for revolving the outer shell about the axis of the outer shell.The two grip pipes 613 and 614 are provided approximately symmetric withrespect to the axis of the outer shell. When the grip plate 715 istwisted such that the grip pipes 613 and 614 are twisted to each other,a torque about the axis of the outer shell is applied on the outer shellvia the grip pipes 613 and 614. Here, the configuration of themanipulation part may be arbitrary as long as a torque about the axis ofthe outer shell is allowed to be applied on the outer shell.

Similarly to the case of the electronic endoscope 601 described above,in the electronic endoscope 701, the stepping motor 628 is driven by aspecified number of pulses so that the moving lens frame section 604 isrevolved inside the electronic endoscope 701 so as to advance or retreatin the axial direction. In association with this, the field of view ismoved like No.001→No.002→No.003 . . . as shown in FIG. 53. In thismanner, image pick-up processing and image data accumulation into thememory 626 are repeated so that image pick-up is achieved.

Once image pick-up by the electronic endoscope 701 is completed, thedata accumulated in the image memory 626 is read to the outside. Then,when an abnormality such as disease and a wound is recognized in theimage generated from the read-out data, the image pick-up site where theimage data was acquired need be identified. Thus, in the beginning ofimage pick-up, the attitude angle of the outer shell about the axis ofthe outer shell of the electronic endoscope 701 is set up at apredetermined angle relative to the hole serving as a subject bymanipulating the manipulation part composed of the grip pipes 613 and614 and the grip plate 715.

For example, in the state that the moving lens frame section 604 islocated at the home position shown in FIG. 57, the field of view of theelectronic endoscope 701 is directed to the one grip pipe 613 side inthe direction of arrangement of the two grip pipes 613 and 614. Here, asshown in FIG. 58, a segment L3 is defined as the segment obtained byjoining a reference point P set up arbitrarily at a position on the openend part of the hole serving as a subject to the axis O of the housingof the electronic endoscope 701. Further, a segment L4 is defined as thesegment obtained by joining the grip pipe 613 to the axis O. Then, theangle (attitude angle) θ formed by the segment L3 and the segment L4 isset up at a predetermined angle. By virtue of this, the image pick-upsite where the image data was acquired is identified on the basis of theattitude angle θ, the order of image pick-up of the image data, and theamounts of displacement of the field of view in the axial direction andthe circumferential direction at predetermined image pick-up intervals.

As described above with reference to the electronic endoscope 701serving as an example, the present specification has disclosed anelectronic endoscope that is inserted into a hole and then acquires animage of the inner peripheral surface of the hole, characterized bycomprising: an outer shell that is formed in a cylindrical shape andwhose peripheral wall is provided with a transparent window partextending in an axial direction; a solid-state imaging device that isprovided inside the outer shell; an objective optical system thatincludes an objective lens for focusing object light through the windowpart and that forms an image onto the solid-state imaging device; and adrive mechanism that causes at least the objective lens in the objectiveoptical system to move along an axis of the outer shell, wherein amanipulation part used for revolving the outer shell about the axis ofthe outer shell is provided in the bottom part of the outer shell whichfaces the opening of the hole.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the window part is provided over the entirecircumference of the outer shell, and that the drive mechanism causes atleast the objective lens in the objective optical system to revolveabout the axis of the outer shell and thereby moves along the axis ofthe outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the manipulation part includes a plate memberwhich is provided such as to protrude from the bottom part of the outershell, and wherein the plate member is arranged on the axial of theouter shell.

Further, the present specification has disclosed a method of imagepick-up characterized by comprising the steps of: inserting anelectronic endoscope into a hole; manipulating a manipulation partprovided in the bottom part of the outer shell that faces the opening ofthe hole so as to set up the attitude angle of the outer shell about theaxis of the outer shell relative to the hole to a predetermined angle;and acquiring an image of the inner peripheral surface of the hole inthe course that the drive mechanism moves the objective lens along theaxis of the outer shell.

Further, the present specification has disclosed a method of imagepick-up characterized in that the window part is provided over theentire circumference of the outer shell, and wherein the drive mechanismcauses at least the objective lens in the objective optical system torevolve about the axis of the outer shell and thereby moves along theaxis of the outer shell.

An electronic endoscope 801 shown in FIGS. 59 and 60 includes: an outershell having a body part 602 and a transparent capsule 603; and a movinglens frame section 604 and an image pick-up drive unit part 605accommodated in the inside of the outer shell. Here, like members tothose of the electronic endoscope 601 described above are designated bylike numerals, and functionally common members are designated byappropriately corresponding numerals. Then, their description is omittedor simplified.

In the electronic endoscope 801, a power switch 847 is provided. Asshown in FIG. 61, in the state that the electronic endoscope 801 isinserted into a hole serving as a subject, the power switch 847 can beoperated from the outside of the hole. In the example shown in thefigure, the power switch 847 is turned ON or OFF by manual operation,and is provided in the bottom part 602 a of the body part 602 that facesthe opening of the hole. Here, the power switch 847 may be provided inthe battery lid 612 that is fitted in the opening part of the batteryaccommodating part 602 b formed in the bottom part 602 a and thatconstitutes a part of the bottom part 602 a. In another exemplaryconfiguration for the power switch, a remote code may be extracted fromthe body part 602 to the outside of the hole and then a manipulationpart used for performing ON-OFF operation may be provided in the endpart. In yet another exemplary configuration for the power switch, aswitch terminal that follows magnetism may be built in the body part602. Then, from the outside of the hole, a magnet is brought close to orapart from the body part 602 so that the switch terminal may be turnedON or OFF.

When the power switch 847 is turned ON, as shown in FIG. 62, electricpower from the power battery 611 is supplied through wiring (not shown)to the individual parts of the image pick-up drive unit part 605, sothat image pick-up operation and drive operation are performed similarlyto the case of the electronic endoscope 601 described above.

As described above with reference to the electronic endoscope 801serving as an example, the present specification has disclosed anelectronic endoscope that is inserted into a hole and then acquires animage of the inner peripheral surface of the hole, characterized bycomprising: an outer shell that is formed in a cylindrical shape andwhose peripheral wall is provided with a transparent window partextending in an axial direction; a solid-state imaging device that isprovided inside the outer shell; an objective optical system thatincludes an objective lens for focusing object light through the windowpart and that forms an image onto the solid-state imaging device; adrive mechanism that causes at least the objective lens in the objectiveoptical system to move along an axis of the outer shell; a controlsection that controls the solid-state imaging device and the drivemechanism; and an operation switch that operates the control section,wherein in a state that the electronic endoscope is inserted into thehole, the operation switch is allowed to be operated from the outside ofthe hole.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the operation switch is provided in the bottompart of the outer shell that faces the insertion opening of the hole.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the window part is provided over the entirety ofthe circumferential wall of the outer shell, and wherein the drivemechanism causes at least the objective lens in the objective opticalsystem to revolve about the axis of the outer shell and thereby movesalong the axis of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the outer shell is formed in a cylindrical shapeand a thread groove is formed in the inner peripheral surface of thecircumferential wall, wherein the drive mechanism includes a lens holderwhich supports the objective lens and a motor which drives and revolvesthe lens holder about the axis of the outer shell, and wherein the lensholder engages with the thread groove of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the control section reads an image pick-up signalfrom the solid-state imaging device and generates image data, andwherein a memory which stores the image data is further included in theinside of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the drive mechanism is driven by electric power,and wherein a power battery which supplies electric power to thesolid-state imaging device, the drive mechanism, and the control sectionis further provided inside the outer shell.

In the electronic endoscope 901 shown in FIG. 63, in place of theobjective mirror 616 in the electronic endoscope 601 described above, ahalf mirror 931 is arranged in the cylindrical hole 604 e of theobjective lens mount part 604 a. Then, an illumination lens 932 and anLED 933 is provided behind the half mirror 931. Here, like members tothose of the electronic endoscope 601 described above are designated bylike numerals, and functionally common members are designated byappropriately corresponding numerals. Then, their description is omittedor simplified.

In the electronic endoscope 601 described above, the LED 633 is arrangedon the reflected light path of the object light reflected from the halfmirror 631, and the solid-state imaging device 627 is arranged on thetransmitted light path of the object light transmitted through the halfmirror 631. In contrast, in the electronic endoscope 901, the LED 933 isarranged on the transmitted light path of the object light transmittedthrough the half mirror 931, and the solid-state imaging device 627 isarranged on the reflected light path of the object light reflectedthrough the half mirror 931. Even in this configuration, light forillumination is projected through the objective lens 617 onto theimage-taking object.

As described above with reference to the electronic endoscopes 601 and901 serving as examples, the present specification has disclosed anelectronic endoscope characterized by comprising: an outer shell that isformed in a tube shape and whose peripheral wall is provided with atransparent window part extending in an axial direction; a light sourceand a solid-state imaging device that are provided inside the outershell; an illumination optical system that projects light forillumination from the light source through the window part onto animage-taking object; an objective optical system that includes anobjective lens which focuses object light through the window part andthat forms an image onto the solid-state imaging device; and a drivemechanism that causes at least the objective lens in the objectiveoptical system to move along an axis of the outer shell, wherein theillumination optical system projects the light for illumination onto theimage-taking object through the objective lens.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the illumination optical system includes a halfmirror; the half mirror is arranged on the optical path of the objectlight in an inclined manner relative to the optical axis of the objectlight in the objective optical system; the light source is arranged onany one of the transmitted light path of the object light transmittedthrough the half mirror and the reflected light path of the object lightreflected from the half mirror; and the solid-state imaging device isarranged on the other one of the transmitted light path and thereflected light path.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the window part is provided over the entirety ofthe circumferential wall of the outer shell, and wherein the drivemechanism causes at least the objective lens in the objective opticalsystem to revolve about the axis of the outer shell and thereby movesalong the axis of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the outer shell is formed in a cylindrical shapeand a thread groove is formed in the inner peripheral surface of thecircumferential wall, wherein the drive mechanism inch ides a lensholder which supports the objective lens and a motor which drives andrevolves the lens holder about the axis of the outer shell, and whereinthe lens holder engages with the thread groove of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a control section which reads an image pick-upsignal from the solid-state imaging device and which generates imagedata and a memory which stores the image data are further included inthe inside of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the drive mechanism is driven by electric power,and wherein a power battery which supplies electric power to thesolid-state imaging device and the drive mechanism is further providedinside the outer shell.

An electronic endoscope 1001 shown in FIGS. 64 to 66 includes: an outershell having a body part 602 and a transparent capsule 603; and a movinglens frame section 604 and an image pick-up drive unit part 605accommodated in the inside of the outer shell. Here, like members tothose of the electronic endoscope 601 described above are designated bylike numerals, and functionally common members are designated byappropriately corresponding numerals. Then, their description is omittedor simplified.

Then, in place of the illumination optical system of the above-mentionedelectronic endoscope 601 which is constructed from the LED 633, theillumination lens 632, the half mirror 631, the objective mirror 616,and the objective lens 617, in the electronic endoscope 1001, the upperpart of the objective lens mount part 604 a of the moving lens framesection 604 is provided with: a light emitting diode (LED) 1033 foremitting light for illumination; an illumination lens 1032 for facingthe light for illumination from the LED 1033 and then projects the lightonto the image-taking object; and a battery 1034 for supplying electricpower to the LED 1033.

The illumination lens 1032 serving as a projection exit of the light forillumination is arranged above the objective lens 617 such that the lensoptical axis of the illumination lens 1032 is in parallel to the lensoptical axis of the objective lens 617 or alternatively such that thelens optical axis of the illumination lens 1032 approaches the lensoptical axis of the objective lens 617 when going outward from the outershell. The light for illumination projected from the illumination lens1032 onto the image-taking object illuminates the region containing theview field region of the objective lens 617. The LED 1033, theillumination lens 1032, and the battery 1034 are fixed to the objectivelens mount part 604 a by fixing members (not shown).

Here, the illumination lens 1032 serving as a projection exit of thelight for illumination is preferably arranged at a position adjacent tothe objective lens 617 in the axial direction of the outer shell. Byvirtue of this, for example, in a case that an image-taking objectlocated extremely close is to be taken, illumination of the regioncontaining the view field region of the objective lens 617 becomes easy.

In the above-mentioned configuration that the LED 1033 and theillumination lens 1032 are exposed to the outside of the objective lensmount part 604 a, its ON-OFF state is easily checked through thetransparent capsule 603 and hence a possible trouble is recognizedeasily. Further, electric power to the LED 1033 is supplied from thebattery 1034 separate from the power battery 611. Thus, even in a casethat the LED 1033 is of high luminance, its relatively high powerconsumption among those of LEDs is satisfactorily covered by the battery1034. Thus, this configuration realizes a clear image.

In the electronic endoscope 1001, a power switch (not shown) isprovided. When the power switch is turned ON, electric power from thepower battery 611 is supplied through wiring (not shown) to theindividual parts of the image pick-up drive unit part 605. Further,electric power from the battery 1034 is supplied through wiring (notshown) to the LED 1033. By virtue of this, image pick-up operation anddrive operation are performed.

FIG. 67 is a functional block diagram showing the image pick-up driveunit part 605. The CPU 641 for collectively controlling the entiresystem is connected to: a control memory 642 that stores a controlprogram and serves also as a work memory; an image memory 626 providedon the base plate 622; an LED drive circuit 643 for driving the LED1033; an imaging device driver 644 for driving the imaging device 627;and a pulse generator 646 for providing driving pulses to the motordriver 645 for driving the stepping motor 628.

When the power switch 647 is turned ON, electric power is supplied fromthe power batteries 611 and 1034 to the individual parts so thatoperation is started. Thus, the stepping motor 628 is driven andrevolved. Accordingly, the moving lens frame section 604 is revolved inthe inside of the electronic endoscope 1001 so as to advance or retreatin the axial direction.

With reference to FIG. 66, the light for illumination from the LED 1033enters the illumination lens 1032. Then, the light for illuminationhaving entered the illumination lens 1032 is transmitted through thetransparent capsule 603 and then projected toward the image-takingobject so as to serve as light for illumination that illuminates theimage-taking object contained in the view field region of the objectivelens 617. That is, the illumination lens 1032 constitutes anillumination optical system.

The light for illumination is reflected by the image-taking object.Then, a part of the reflected light serving as object light enters theobjective lens 617.

The object light having entered the objective lens 617 is brought intothe form of a parallel light beam, then travels to the objective mirror616, and then is reflected by the objective mirror 616 so as to travelto the focusing lens 630 with maintaining the form of a parallel lightbeam. Then, the object light is focused onto the light acceptancesurface of the solid-state imaging device 627 by the focusing lens 630so that an image is formed.

The image pick-up signal of the image-taking object acquired by theimaging device 627 is acquired into the CPU 641 so as to undergo imageprocessing, and then stored into the image memory 626, for example, inthe form of JPEG image data.

Similarly to the case of the electronic endoscope 601 described above,in the electronic endoscope 1001, the stepping motor 628 is driven by aspecified number of pulses so that the moving lens frame section 604 isrevolved inside the electronic endoscope 1001 so as to advance orretreat in the axial direction. In association with this, the field ofview is moved like No.001→No.002→No.003 . . . as shown in FIG. 53. Inthis manner, image pick-up processing and image data accumulation intothe memory 626 are repeated so that image pick-up is achieved.

After the image pick-up of an object image of the field of view “No.001”shown in FIG. 53, the stepping motor 628 is driven by a specified numberof pulses. Thus, the moving lens frame section 604 is revolved by thespecified number of pulses. As a result, the moving lens frame section604 is screwed and retreats into the body part 602. In association withthis, the objective lens 617 held by the moving lens frame section 604is moved so that the field of view moves to “No.002” shown in FIG. 53.At that time, the LED 1033 and the illumination lens 1032 mounted on themoving lens frame section 604 are also moved similarly to the objectivelens 617, and thereby follows the moving field of view so as toilluminate the field of view “No.002”. Then, an object image in thisfield of view is taken, and then the obtained image data is accumulatedin the image memory 626.

FIG. 68 shows a state that the moving lens frame section 604 has gonehalf around inside the transparent capsule 603 starting from the stateshown in FIG. 66. When the moving lens frame section 604 has gone onearound from the home position inside the transparent capsule 603, thefield of view of image pick-up is located at No.011 in FIG. 53. In caseof having gone around twice, the field of view of image pick-up islocated at No.021 in FIG. 53.

Further, FIG. 69 shows a state that the lower end of the cylindricalmember 604 b abuts against the bottom part 602 a of the body part 602and hence cannot move further in this direction. When the state shown inFIG. 69 is reached, the processing loop of repeating the image pick-upprocessing is terminated.

Once image pick-up by the electronic endoscope 1001 is completed, thedata accumulated in the image memory 626 is to be read to the outside.

As described above with reference to the electronic endoscope 1001serving as an example, the present specification has disclosed anelectronic endoscope characterized by comprising: an outer shell that isformed in a tube shape and whose peripheral wall is provided with atransparent window part extending in an axial direction; a light sourceand a solid-state imaging device that are provided inside the outershell; an illumination optical system that projects light forillumination from the light source through the window part onto animage-taking object; an objective optical system that includes anobjective lens which focuses object light through the window part andthat forms an image onto the solid-state imaging device; a lens holderthat holds at least the objective lens in the objective optical system;and a driving section that moves the lens holder along the axis of theouter shell, wherein the light source and the illumination opticalsystem are integrally fixed and supported by the lens holder.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the projection exit of the illumination opticalsystem is arranged at a position adjacent to the objective lens in theaxial direction of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the window part is provided over the entirecircumference of the peripheral wall of the outer shell, and wherein thedriving section causes the lens holder to revolve about the axis of theouter shell and thereby moves along the axis of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the outer shell is formed in a cylindrical shapeand its inner peripheral surface is provided with a thread groove,wherein the driving section includes a motor which chives and revolvesthe lens holder about the axis of the outer shell, and wherein the lensholder engages with the thread groove of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a control section which reads an image pick-upsignal from the solid-state imaging device and then generates image dataand a memory which stores the image data are further included in theinside of the outer shell.

Further; the present specification has disclosed an electronic endoscopecharacterized in that the driving section is driven by electric power,and wherein a power battery which supplies electric power to the lightsource, the solid-state imaging device, and the driving section arefurther provided inside the outer shell.

An electronic endoscope 1101 shown in FIGS. 70 to 72 includes: a bodypart 602 and a transparent capsule 603 that constitute an outer shell; amoving lens frame section 604 accommodated in the inside; and an imagingunit part 1105 and a storage and driving section 1106 described later.Here, like members to those of the electronic endoscope 601 describedabove are designated by like numerals, and functionally common membersare designated by appropriately corresponding numerals. Then, theirdescription is omitted or simplified.

In the electronic endoscope 601 described above, the body part 602 andthe transparent capsule 603 were fixed to each other by bonding. Incontrast, in the electronic endoscope 1101, the body part 602 and thetransparent capsule 603 are fixed to each other by screwing. That is, ascrewing protrusion part 602 e having a somewhat smaller diameter thanthe body part 602 protrudes from the open end part 602 d of the bodypart 602. Then, a male screw is engraved spirally in the outerperipheral surface of the screwing protrusion part 602 e. Further, inthe inner peripheral surface of the open end part 603 b on the sideopposite to the hemispherical part 603 a of the transparent capsule 603,a female screw is engraved spirally that screws into the male screw inthe screwing protrusion part 602 e on the body part 602 side.

The imaging unit 1105 individual colors base plates 1121 and 1122. Thebase plates 1121 and 1122 are mounted on and fixed to the objective lensmount part 604 a inside the cylindrical member 604 b at a positiondeparting from the cylindrical member 604 b. In the base plate 1121arranged on the upper side (the objective lens mount part 604 a side), acylindrical lens holder 1129 is arranged in the center part. Then, asolid-state imaging device 1127 is mounted on the base plate 1121 in theinside.

A focusing lens 1130 is mounted in the upper opening of the lens holder1129. Then, the parallel light beam reflected by the objective mirror616 is focused by the focusing lens 1130 so that an image is formed ontothe light acceptance surface of the solid-state imaging device 1127.

The moving lens frame section 604 includes: an LED 1133 installed on theupper part of the objective lens mount part 604 a; and an illuminationlens 1132 arranged in front of the LED 1133. The LED 1133 emits lightfor illumination. Then, the light for illumination focused by theillumination lens 1132 illuminates an image-taking object located infront of the objective lens 617.

A first control unit 1125 described later is mounted on the base plate1122 arranged on the lower side. A battery accommodating part 1122 a isprovided in the lower surface of the base plate 1122. Then, a secondpower battery 1111 b is accommodated here. The second power battery 1111b is mounted in the battery accommodating part 1122 a in a situationthat the screwing between the female screw 603 b of the transparentcapsule 603 and the male screw 602 e of the body part 602 is released sothat the electronic endoscope 1101 is disassembled.

The first control unit 1125 receives driving power from the second powerbattery 1111 b. Further, the LED 1133 receives driving power from thesecond power battery 1111 b through wiring (not shown).

The storage and driving section 1106 is mounted and fixed in the insideof the body part 602 by using a stay member (not shown) in a state thatthe peripheral wall of the battery accommodating part 602 b provided inthe bottom part 602 a of the body part 602 serves as a supportingcolumn. The storage and driving section 1106 has a base plate 1123.

On the base plate 1123, a second control unit 1124 is fixed and mounted,and a stepping motor 1128 is also fixed and mounted. Then, a motor gearwheel (spur wheel) 1136 is attached to the shaft of the stepping motor1128. The shaft of the stepping motor 1128 is oriented in parallel tothe center axis of the cylindrical member 604 b (the optical axis of theparallel light beam). Then, the motor gear wheel 1136 engages with anidle gear wheel 1137 composed of a spur wheel.

The shaft of the idle gear wheel 1137 is pivotally supported in arevolvable manner in a direction perpendicular to the base plate 1123.The idle gear wheel 1137 has a larger number of gear teeth than themotor gear wheel 1136. Thus, the revolution of the stepping motor 1128is slowed down and then transmitted to the idle gear wheel 1137. Theidle gear wheel 1137 engages with the internal-tooth gear 604 d providedin the inner peripheral surface of the cylindrical member 604 b.

When the stepping motor 1128 revolves, the idle gear wheel 1137revolves. Then, in association with this, the cylindrical member 604 brevolves. When the cylindrical member 604 b revolves, the cylindricalmember 604 b of the moving lens frame section 604 is screwed into or outfrom the body part 602 depending on the direction of revolution. Thatis, the moving lens frame section 604 advances or retreats in the axialdirection.

In the electronic endoscope 1101, a power switch (not shown) isprovided. When the power switch is turned ON, electric power from thefirst power battery 1111 a is supplied to the individual parts of thestorage and driving section 1106 through wiring (not shown) so thatdrive operation is performed.

Further, in the imaging unit 1105, a switch terminal that followsmagnetism is built in. When a magnet is brought close or apart in theoutside of the electronic endoscope 1101, the switch terminal is turnedON or OFF so that power supply from the second power battery 1111 b tothe imaging unit 1105 is turned ON or OFF.

FIG. 73 is a functional block diagram showing the first control unit1125 The CPU 1141 for collectively controlling the imaging unit 1105 isconnected to: a control memory 1142 for storing a control program andserving also as a work memory; an LED drive circuit 1143 for driving theLED 1133; an imaging device driver 1144 for driving the imaging device1127; and a wireless communication module 1148 for perforating wirelesscommunication with the second control unit 1124. An antenna 1148 a isprovided in the wireless communication module 1148.

FIG. 74 is a functional block diagram showing the second control unit1124. The CPU 1149 for collectively controlling the entire system isconnected to: a control memory 1151 for storing a control program andserving also as a work memory; an image memory 1126 for storing imagedata received from the imaging unit 1105 by wireless; a pulse generator1146 for providing driving pulses to a motor driver 1145 for driving thestepping motor 1128; and a wireless communication module 1152 forperforming wireless communication with the first control unit 1125. Anantenna 1152 a is provided in the wireless communication module 1152.

The CPU 1149 of the second control unit 1124 cooperates with the CPU1141 of the first control unit 1125 via wireless communication.

When the power switch described above is turned ON, electric power issupplied from the first power battery 1111 a and the second powerbattery 1111 b to the individual parts so that operation is started.Then, the motor 1128 is driven and revolved. Accordingly, the movinglens frame section 604 is revolved in the inside of the electronicendoscope 1101 so as to advance or retreat in the axial direction.Further, the emitted light from the LED 1133 is focused by theillumination lens 1132, and then projected toward the image-takingobject so as to serve as light for illumination.

The reflected light from the image-taking object is acquired through theobjective lens 617 into the electronic endoscope 1101. Then, the opticalimage of the image-taking object reflected by the objective mirror 616travels to the focusing lens 1130 in the form of a parallel light beam,and then is focused onto the light acceptance surface of the solid-stateimaging device 1127 by the focusing lens 1130 so that an image isformed.

The image pick-up signal of the image-taking object acquired by theimaging device 1127 is acquired into the CPU 1141 and then undergoesimage processing so as to be converted, for example, into JPEG imagedata. The obtained data is acquired into the CPU 1149 via wirelesscommunication modules 1148 and 1152, and then stored into the imagememory 1126.

FIG. 75 is a flow chart showing the processing procedure of a controlprogram stored in the control memory 1151. When the power switch isturned ON, this control program is started. Then, first, the steppingmotor 1128 is driven to the home position side (step S1). Here, the homeposition side indicates, for example, the state shown in FIG. 72 wherethe objective lens 617 is located on the tip side of the electronicendoscope 1101.

In this embodiment, for the purpose of cost reduction, a sensor is notprovided that detects whether the stepping motor 1128 has reached thehome position. Thus, at the next step S2, it is judged whether a timerfor counting a predetermined time has counted up. Then, when thepredetermined time has not yet elapsed, step S1 is executed repeatedly.In a configuration that a sensor for detecting reaching to the homeposition is provided, step S1 is merely executed repeatedly untilreaching to the home position is detected by the sensor.

It is sufficient that the predetermined time is defined as the longesttime necessary for the stepping motor 1128 to reach the home position.For example, the state shown in FIG. 76 is a state that the moving lensframe section 604 has revolved and moved to the lowermost position.Thus, the predetermined time may be defined as the time necessary fromthis state to a state that the moving lens frame section 604 hasrevolved in association with the revolution of the stepping motor 1128so as to have reached the home position (a position where the movinglens frame section 604 abuts against the inner peripheral surface of thehemispherical part 603 a and hence cannot move further in thisdirection) shown in FIG. 72.

By virtue of this, even in a case that the moving lens frame section 604is located wherever in the middle between the state shown in FIG. 72 andthe state shown in FIG. 76 (a state that the lower end of thecylindrical member 604 b abuts against the bottom part 602 a of the bodypart 602), the objective lens 617 necessarily reaches the home positionwhen the stepping motor 1128 is driven in the home position direction bythe predetermined time.

When the timer has counted the predetermined time, the procedure goesfrom step S2 to step S3 where the contents of a counter described lateris cleared into zero. Then, the procedure goes to step S4 where imagepick-up processing is performed. In the image pick-up processing: theLED 1133 is turned ON so that light for illumination is projectedthrough the objective lens 617; light reflected from the image-takingobject is acquired through the objective lens 617 into the electronicendoscope 1101; and then the incident light from the image-taking objectis focused onto the light acceptance surface of the imaging device 1127so that an image is formed.

Then, the CPU 1141 drives the imaging device 1127 via the imaging devicedriver 1144 so as to acquire from the imaging device 1127 the imagepick-up signal of the image-taking object obtained by the imaging device1127, then performs image processing, and then transmits the obtaineddata to the second control unit 1124. Then, the CPU 1149 of the secondcontrol unit 1124 stores the data into the image memory 1126.

At the next step S5, the stepping motor 1128 is driven by a specifiednumber of pulses. At the next step S6, this specified number of pulsesis added to the count value in the counter. At the next step S7, thetotal count value in the counter is compared with a specified number.

Then, when the total count value in the counter does not reach thespecified number, the procedure returns from step S7 to step S4 so thatimage pick-up processing is performed. After that, the processing loopof steps S4 to S7 is executed repeatedly. When the total count value inthe counter has reached the specified number, the processing shown inFIG. 75 is terminated.

FIG. 77 is a diagram illustrating the movement of the field of view ofimage pick-up of the objective lens 617 in a case that step S4 in FIG.75 is executed repeatedly. In the first occasion of image pick-upprocessing performed at the home position, an object image in the fieldof view indicated by “No.001” in FIG. 77 is acquired from the imagingdevice 1127.

After the image pick-up for the object image of the field of view“No.001”, the stepping motor 1128 is driven at step S5 by a specifiednumber of pulses. Thus, the cylindrical member 604 b revolves by thespecified number of pulses. As a result, the cylindrical member 604 b isscrewed and withdrawn into the body part 602. Thus, the next field ofview is located at “No.002” in FIG. 77. Then, an object image in thisfield of view is taken, and then the obtained image data is accumulatedin the image memory 1126.

After that, during the operation of moving the field of view likeNo.003→No.004→No.005 . . . , image pick-up processing and image dataaccumulation into the memory 1126 are repeated. FIG. 78 shows a statethat the moving lens frame section 604 has gone half around inside thetransparent capsule 603 starting from the state shown in FIG. 72. FIG.79 shows a state, of one around starting from the state shown in FIG.72.

When the moving lens frame section 604 has gone one around from the homeposition within the transparent capsule 603, the field of view of imagepick-up is located at No.011 in FIG. 77. In case of having gone aroundtwice, the field of view of image pick-up is located at No.021 in FIG.77.

Further, FIG. 76 shows a state that the lower end of the cylindricalmember 604 b abuts against the bottom part 602 a of the body part 602and hence cannot move further in this direction. When the state shown inFIG. 76 is reached, the processing loop of repeating the image pick-upprocessing (step S4) is terminated. Accordingly, the “specified number”used at step S7 in FIG. 75 is equal to the total number of pulsesnecessary for reaching from the home position to the state shown in FIG.76.

Once image pick-up by the electronic endoscope 1101 is completed, thedata accumulated in the image memory 1126 is to be read to the outside.

In the electronic endoscope 1101 described above, the objective mirror616 is provided on the center axis. Then, the light acceptance surfaceof the imaging device 1127 is provided on this center axis, and theimage pick-up hole 604 f is provided straight in a radial direction. Byvirtue of this, the objective mirror 616 bends the optical path by 90degrees so that the light beam enters the imaging device 1127 on thecenter axis. In contrast, in the present example, the mutual positionalrelation between the objective lens 617, the objective mirror 616, andthe imaging device 1127 is fixed regardless of the revolution of themoving lens frame section 604. Thus, the position of the imaging device1127, the position of the objective mirror 616, its reflection angle,and the direction of the image pick-up hole 604 f may be set uparbitrarily as long as they do not interfere with the revolution motionof the moving lens frame section 604.

Further, the above-mentioned description has been given for a case thatthe incident light is brought into the form of a parallel light beam bythe objective lens 617 and then is reflected by the objective mirror 616with maintaining the form of a parallel light beam. However, since themutual position relation between the objective lens 617, the objectivemirror 616, and the imaging device 1127 is fixed, the form of the lightbeam is not limited to a parallel beam. Thus, a zoom lens may beinserted in the middle of the optical path so that an enlarged imagecorresponding to the original image may be acquired.

As described above with reference to the electronic endoscope 1101serving as an example, the present specification has disclosed anelectronic endoscope characterized by comprising: a transparent cover atleast whose observation window in a cylindrical part is transparent; abody part that has a cylindrical part provided continuously to thecylindrical part of the transparent cover; a lens holder that revolvesabout the center axis of the transparent cover in the inside of thetransparent cover and the body part so as to move in the direction ofthe center axis; an objective mirror that is provided in the lens holderand that reflects, toward the body part, light entering through anobjective lens provided at a position facing the cylindrical part of thetransparent cover; an imaging device that is fixed and mounted in thelens holder and that receives the light reflected from the objectivemirror so as to convert the light into an electric signal; and a drivingsection that is provided inside the body part and that drives andrevolves the lens holder so as to drive the lens holder in the centeraxis direction.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the lens holder includes: a disk-shaped member onwhich the objective lens is mounted and the objective mirror is mounted;and a cylindrical member provided integrally and continuously to thebody part side of the disk-shaped member.

Further, the present specification has disclosed an electronic endoscopecharacterized by comprising: a female screw that is engraved spirally inthe inner peripheral surface of the body part; and a male screw that isengraved spirally in the outer peripheral surface of the cylindricalmember, that engages with the female screw and that, when thecylindrical member is driven and revolved by the driving section, movesthe cylindrical member in the center axis direction.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a control section that performs image processingonto the image signal acquired by image pick-up performed by the imagingdevice and that transmits by wireless the image data having undergonethe image processing is fixed and mounted in the lens holder.

Further, the present specification has disclosed an electronic endoscopecharacterized in that an image memory which receives and stores theimage data transmitted by wireless as described above is provided in thebody part.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the transparent cover and the body part areprovided continuously to each other by screwing in a manner permittingdisassembly.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the drive power supply for the imaging device andthe drive power supply for the driving section are provided as separatemembers.

The electronic endoscope 1200 shown in FIG. 80 includes: a body part1211 serving as an outer shell; a transparent cover 1213 having a tubebody at least whose side surface has transparency; an introductoryoptical part 1215 accommodated inside the outer shell; and an imagepick-up drive unit part 1217 (see FIG. 81) serving as an image pick-upsection described later.

FIG. 81 is a longitudinal sectional view of the electronic endoscope1200. FIG. 82 is an exploded perspective view of the electronicendoscope 1200. The body part 1211 is formed in a closed-bottomcylindrical shape fabricated from resin material or the like. Its bottompart (lower side in FIG. 81) 1211 a is provided with a tube-shapedbattery accommodating part 1211 b. After a power battery 1219 ismounted, the battery accommodating part 1211 b is airtightly closed by abattery lid 1221.

Further, in the bottom part 1211 a, in the example shown in the figure,two hard grip pipes 1223 and 1225 fabricated from resin are fixed in aprotruding manner toward the outside. Then, when the grip pipes 1223 and1225 are manipulated by hand, the entirety of the electronic endoscope1200 is inserted into or extracted from a hole or an abdominal cavityserving as a subject. The electronic endoscope 1200 may be used in aconfiguration that wiring is inserted through the grip pipes 1223 and1225.

The transparent cover 1213 is formed from hard transparent resin. Itsone-end part (tip part) is closed and formed in a smooth hemisphericalshape that permits easy insertion into the inside of a subject. An openend part 1213 b that is located on the side opposite to thehemispherical part 1213 a and has an expanded diameter and an open endpart 1211 d of the body part 1211 are aligned to each other and fixed bybonding. The transparent cover 1213 may be fabricated by integralmolding. Alternatively, the hemispherical part 1213 a, the open end part1213 b, and the like may be fixed to the transparent cylinder body bybonding in a multi-piece configuration. Further, light shieldingproperty may be imparted to the hemispherical part 1213 a so that it maybe prevented that external light is introduced directly into theobjective lens 1277. Here, it is sufficient that the transparent resinis transparent to light at a particular wavelength. That is, thematerial need not be transparent to visible light.

The transparent cover 1213 having the above-mentioned configuration soas to cover the introductory optical part 1215 is formed in a smallerdiameter than the body part 1211. Further, one-end side of thetransparent cover 1213 in the form of a tube body has a smaller diameterthan the body part 1211. Thus, a stepped part (open end part 1213 b)whose diameter expands in the radial direction of the transparent cover1213 is formed in a part of the outer shell. That is, the stepped partis formed by the diameter difference between the transparent cover 1213and the body part 1211. When the diameter is reduced in the tip of theelectronic endoscope 1200 as described here, observation of the insideof the subject becomes easy. This extends the range of application ofthe electronic endoscope, like observation of a site having an extremelysmall diameter in the subject. Here, the transparent cover 1213 may bein the form of a frontward-tapered shape having a stepped part. Thisconfiguration permits much easier insertion of the tip insert part ofthe body part 1211 into a small hole or a small abdominal cavity.

In the inside of the body part 1211, a lens drive ring 1285 serving as acylindrical revolving body is arranged. On the transparent cover 1213side (upper side in the figure) of the lens drive ring 1285, a movinglens frame 1285 c connected to the introductory optical part 1215 isprovided continuously. On the tip side of the moving lens frame 1285 c,an objective lens holding hole 1275 a serving as an image pick-up holeis formed. Then, an objective lens 1277 is fixed to the objective lensholding hole 1275 a and then acquire light (object light) from thetransparent cover 1213 side. The light acquired from the sideward regionthrough the objective lens 1277 is brought into the form of a parallellight beam, then projected onto the objective mirror 1279 fixed to theinner surface of the moving lens frame 7285 c, then reflected by the45-degree-oblique reflecting surface of the objective mirror 1279, andthen travels toward the imaging device 1249 along the center axis of thetransparent cover 1213 with maintaining the form of a parallel lightbeam.

FIG. 83 shows an enlarged perspective view of a part containing theimage pick-up drive unit part 1217. On the base plate 1241 in thelowermost layer (on the bottom part 1211 a side), a control unit 1245 isarranged that includes a driver circuit for the stepping motor servingas a driving source of the raising and lowering driving section. On thebase plate 1242 in the middle layer, an image memory 1247 for storingpick-up image data is arranged. On the base plate 1243 in the upperlayer, an imaging device 1249 is arranged that is composed of asolid-state imaging device such as a CCD type imaging device and a CMOStype imaging device.

On the base plate 1243, a focusing lens holder 1251 formed in acylindrical shape is arranged. Then, the imaging device 1249 isaccommodated inside the focusing lens holder 1251. Then, a focusing lens1253 is arranged in the upper-end opening part of the focusing lensholder 1251. Thus, the guided parallel light beam (object light) L1 isfocused onto the light acceptance surface of the imaging device 1249 bythe focusing lens 1253 so that an image is formed.

Further, a half mirror 1255 is arranged in the middle of the opticalpath between the introductory optical part 1215 and the imaging device1249 so that an illumination optical system is added. In theillumination optical system, the emitted light from the light emittingdiode (LED) 1257 serving as a light emitting body is projected as lightfor illumination L2 toward the introductory optical part 1215 after thereflection by the half mirror 1255. That is, the half mirror 1255 isarranged at a position in the immediate upstream of the focusing lens1253 within the parallel light beam entering the focusing lens 1253 in astate that the half mirror 1255 is inclined by 45 degrees relative tothe optical axis of the parallel light beam (the center axis of the bodypart 1211). Then, an illumination lens 1259 for bringing the light forillumination in the form of a parallel light beam is arranged betweenthe LED 1257 and the half mirror 1255. The half mirror 1255, theillumination lens 1259, and the LED 1257 are fixed inside the body part1211 individually by appropriate support members (not shown).

FIGS. 84A and 84B are diagrams showing operation of the moving lensframe provided with the objective lens. FIG. 84A is an enlargedperspective view of a part showing a raised position. FIG. 84B is anenlarged perspective view of a part showing a lowered position. Theintroductory optical part 1215 revolves about the center axis of thetransparent cover 1213 and, in accordance with this, rises or goes lowerin the axis direction in the inside of the transparent cover 1213. Theintroductory optical part 1215 is provided at the tip of the tube-shapedmoving lens frame 1285 c, and projects light for illumination toward theside along a spiral trajectory formed in association with the motionthat the objective lens 1277 arranged on the side part of the movinglens frame 1285 c revolves and moves in the axis direction. At the sametime, the introductory optical part 1215 acquires reflected light fromthe sideward region so as to transfer the object light to the imagingdevice 1249. As shown in FIGS. 81 and 82, the introductory optical part1215 is integrated with the lens drive ring 1285 via the cylindricalmoving lens frame 1285 c, and hence moves in linkage with the revolutionmotion and the raising and lowering motion of the lens drive ring 1285.

Next, a movement mechanism for the lens drive ring 1285 having theintroductory optical part 1215 is described below. As shown in FIGS. 81and 82, in the inner peripheral surface of the body part 1211, aprecision female screw 1211 c is engraved about the axis of the bodypart 1211. Then, the lens drive ring 1285 provided with a male screw1285 a is screwed into the female screw 1211 c. Then, in associationwith its revolution, the lens drive ring 1285 advances or retreats inthe axial direction. Further, an annular gear 1285 b is formed in theinner peripheral surface of the lens drive ring 1285. In the annulargear 12856, gear teeth that are in parallel to the axis and that extendover the entire length in the axial direction of the lens drive ring1285 are formed in the circumferential direction at equal intervals.

A stepping motor 1291 is mounted on the base plate 1243 in the uppermostlayer (on the side opposite to the bottom part 1211 a side). Then, amotor gear wheel (spur wheel) 1293 is attached to the shaft of thestepping motor 1291. The axis of revolution of the stepping motor 1291is oriented in parallel to the center axis of the lens drive ring 1285(the optical axis of the parallel light beam). The motor gear wheel 1293engages with an idle gear wheel 1295 composed of a spur wheel.

The shaft of the idle gear wheel 1295 is pivotally supported in arevolvable manner in a direction perpendicular to the base plate 1243.The idle gear wheel 1295 has a larger number of gear teeth than themotor gear wheel 1293. Thus, the revolution of the stepping motor 1291is slowed down and then transmitted to the idle gear wheel 1295. Theidle gear wheel 1295 engages with the annular gear 1285 b provided inthe inner peripheral surface of the lens drive ring 1285.

FIGS. 85A to 85C are explanation diagrams for the operation of theelectronic endoscope 1200. FIG. 85A shows a state that the lens drivering 1285 has gone half around from the revolution start position. FIG.85B shows a state that the lens drive ring 1285 has gone one around fromthe revolution start position. FIG. 85C shows a retreated position wherethe lens drive ring 1285 has terminated the revolution. When thestepping motor 1291 is driven so that the motor gear wheel 1293 isrevolved, the idle gear wheel 1295 revolves so that the lens drive ring1285 revolves. When the lens drive ring 1285 revolves, depending on thedirection of the revolution, the lens drive ring 1285 is raised orlowered in the axial direction in the inside of the body part 1211. Assuch, the moving lens frame 1285 c revolves, and moves in the axialdirection in the inside of the transparent cover 1213. Thus, the movinglens frame 1285 c revolves, and goes straight gradually. By virtue ofthis, information on the entire field is reflected by the objectivemirror 1279, and then acquired through the focusing lens 1253 into theimaging device 1249. The information on the imaging device 1249 istransmitted to the image memory 1247 in appropriate timing, so thatinformation on the entire field is obtained.

As described above, the annular gear 1285 b, the motor gear wheel 1293,the idle gear wheel 1295, and the stepping motor 1291 constitute araising and lowering driving section serving as a revolution drivingsection. Further, the female screw 1211 c, the lens drive ring 1285, themale screw 1285 a, and the raising and lowering driving sectionconstitute a driving section.

The electronic endoscope 1200 has a power switch (not shown). When thepower switch is turned ON, electric power from the power battery 1219 issupplied through wiring (not shown) to the individual parts of the imagepick-up drive unit part 1217, so that image pick-up operation and driveoperation are performed as described later.

For example, the power switch may be provided in the bottom part 1211 aof the body part 1211, and may be turned ON or OFF by manual operation.Alternatively, a switch terminal that follows magnetism may be built inthe body part 1211. Then, from the outside of the electronic endoscope1200, a magnet may be brought close or apart so that the switch terminalmay be turned ON or OFF.

FIG. 86 is a functional block diagram showing the image pick-up driveunit part 1217. The control section (CPU) 1201 for collectivelycontrolling the entire system is connected to: a memory 1203 that storesa control program and serves also as a work memory and that contains theimage memory 1247 provided on the base plate 1242 described in FIG. 83;an LED drive circuit 1205 for driving the LED 1257; an imaging devicedriver 1207 for driving the imaging device 1249; and a pulse generator1208 for providing driving pulses to the motor driver 1209 for drivingthe stepping motor 1291. Image data obtained by image processing in thecontrol section 1201 is stored into the image memory 1247 built in thebody part 1211. This permits acquisition of an image by the electronicendoscope 1200 in a stand alone mode. Thus, operability is improved incomparison with a system where the image data is sequentiallytransmitted to the outside.

When the power switch 1202 is turned ON, electric power is supplied fromthe power battery 1219 to the individual parts so that operation isstarted. Thus, the stepping motor 1291 is driven and revolved.Accordingly, the moving lens frame 1285 c is revolved in the inside ofthe electronic endoscope 1200 so as to advance or retreat in the axialdirection. Further, emitted light from the LED 1257 is focused into theform of a parallel light beam by the illumination lens 1259. Then, theparallel light beam is reflected toward the objective mirror 1279 by thehalf mirror 1255, and then the parallel light beam reflected by theobjective mirror 1279 is projected toward the image-taking objectthrough the objective lens 1277 so as to serve as light forillumination.

The reflected light from the image-taking object is acquired through theobjective lens 1277 into the electronic endoscope 1200. Then, theoptical image of the image-taking object reflected by the objectivemirror 1279 travels to the focusing lens 1253 in the form of a parallellight beam, and then is focused onto the light acceptance surface of thesolid-state imaging device 1249 by the focusing lens 1253 so that animage is formed.

The image pick-up signal of the image-taking object acquired by theimaging device 1249 is acquired into the CPU 1201 so as to undergo imageprocessing, and then stored into the image memory 1247, for example, inthe form of JPEG image data.

FIG. 87 is a flow chart showing the processing procedure of a controlprogram stored in the memory 1203. When the power switch 1202 is turnedON, this control program is started. Then, first, the stepping motor1291 is driven to the home position side (step S1). Here, the homeposition side indicates, for example, the state shown in FIG. 84A wherethe objective lens 1277 is located on the tip side of the electronicendoscope 1200.

In the electronic endoscope 1200, a sensor is not provided that detectswhether the stepping motor 1291 has reached the home position. Thus, atthe next step S2, it is judged whether a timer for counting apredetermined time has counted up. Then, when the predetermined time hasnot yet elapsed, step S1 is executed repeatedly. In a configuration thata sensor for detecting reaching to the home position is provided, stepS1 is merely executed repeatedly until reaching to the home position isdetected by the sensor.

It is sufficient that the predetermined time is defined as the longesttime necessary for the stepping motor 1291 to reach the home position.For example, the state, shown in FIG. 84B is that the moving lens frame1285 c has revolved and thereby reached the lowermost position hn. Then,the predetermined time may be defined as the time necessary for aprocess that, starting from the lowermost position, the moving lensframe 1285 c revolves in association with the revolution of the steppingmotor 1291 so as to reach the home position (a position where the movinglens frame 1285 c is not allowed to travel further in that direction,for example, because of abutting against the tip of the transparentcover 1213) h1 shown in FIG. 84A.

By virtue of this, even in a case that the moving lens frame 1285 c islocated wherever in the middle between the state shown in FIG. 84A andthe state shown in FIG. 84B (a state that the lower end of the lenschive ring 1285 abuts against the bottom part 1211 a of the body part1211), the objective lens 1277 necessarily reaches the home positionwhen the stepping motor 1291 is driven in the home position direction bythe predetermined time.

When the timer has counted the predetermined time, the procedure goesfrom step S2 to step S3 where the contents of a counter described lateris cleared into zero. Then, the procedure goes to step S4 where imagepick-up processing is performed. In the image pick-up processing: theLED 1257 is turned ON so that light for illumination is projectedthrough the objective lens 1277; light reflected from the image-takingobject is acquired through the objective lens 1277 into the electronicendoscope 1200; and then the incident light from the image-taking objectis focused onto the light acceptance surface of the imaging device 1249so that an image is formed.

Then, the CPU 1201 drives the imaging device 1249 via the imaging devicedriver 1207 so as to acquire from the imaging device 1249 the imagepick-up signal of the image-taking object obtained by the imaging device1249, then performs image processing on the signal, and then stores thedata into the image memory 1247.

At the next step S5, the stepping motor 1291 is driven by a specifiednumber of pulses. At the next step S6, this specified number of pulsesis added to the count value in the counter. At the next step S7, thetotal count value in the counter is compared with a specified number.

Then, when the total count value in the counter does not reach thespecified number, the procedure returns from step S7 to step S4 so thatimage pick-up processing is performed. After that, the processing loopof steps S4 to S7 is executed repeatedly. When the total count value inthe counter has reached the specified number, the processing shown inFIG. 87 is terminated.

FIG. 88 is a diagram illustrating the movement of the field of view ofimage pick-up of the objective lens 1277 in a case that step S4 in FIG.87 is executed repeatedly. In the first occasion of image pick-upprocessing performed at the home position, an object image in the fieldof view indicated by “No.001” in FIG. 88 is acquired from the imagingdevice 1249.

After the image pick-up for the object image of the field of view“No.001”, the stepping motor 1291 is driven at step S5 by a specifiednumber of pulses. Thus, the lens drive ring 1285 revolves by thespecified number of pulses. As a result, the lens drive ring 1285 isscrewed and withdrawn into the body part 1211. Thus, the next field ofview is located at “No.002” in FIG. 88. Then, an object image in thisfield of view is taken, and then the obtained image data is accumulatedin the image memory 1247.

After that, during the operation of moving the field of view likeNo.003→No.004→No.005 . . . , image pick-up processing and image dataaccumulation into the memory 1203 are repeated. FIG. 85A shows a statethat the moving lens frame 1285 c has gone half around inside thetransparent cover 1213 starting from the state shown in FIG. 85B. Whenthe moving lens frame 1285 c has gone one around from the home positioninside the transparent cover 1213, the field of view of image pick-up islocated at No.011 in FIG. 88. In case of having gone around twice, thefield of view of image pick-up is located at No.021 in FIG. 88.

Further, FIG. 85C shows a state that the lower end of the lens drivering 1285 abuts against the bottom part 1211 a of the body part 1211 andhence cannot move further in this direction. When the state shown inFIG. 85C is reached, the processing loop of repeating the image pick-upprocessing (step S4) is terminated. Accordingly, the “specified number”used at step S7 in FIG. 87 is equal to the total number of pulsesnecessary for reaching from the home position to the state shown in FIG.85C.

In the example of movement of the field of view of image pick-upillustrated in FIG. 88, the specified number of pulses at step S5 inFIG. 87 is set up such that in the direction of revolution of the movinglens frame 1285 c serving as a revolving body, adjacent fields of viewof image pick-up are positioned such that their left and right edgeparts should be in contact with each other or overlapping somewhat witheach other. Further, the pitch of the screw threads provided in theinner peripheral surface of the body part 1211 and the outer peripheralsurface of the lens drive ring 1285 is designed such that axiallyadjacent fields of view of image pick-ups are positioned such that theirupper and lower edge parts should be in contact with each other oroverlapping somewhat with each other.

By virtue of this, without a missing part over the entirety of thecylindrical field of view region of the inner peripheral surface of theimage-taking object serving as an observation object, image pick-up isachieved so that image data is acquired. The number of pulses for thestepping motor 1291 may be set up, or alternatively the pitch of thefemale screw 1211 c and the male screw 1285 a may be designed such thatlarger overlapping parts should be generated in the fields of view ofimage pick-up.

Once image pick-up by the electronic endoscope 1200 is completed, thedata accumulated in the image memory 1247 shown in FIG. 83 is to be readto the outside. This read operation may be performed by wireless, oralternatively by using a wiring inserted through the grip pipes 1223 and1225 shown in FIG. 80. Alternatively, the image memory 1247 may beprovided in a removable manner from the electronic endoscope 1200. Then,the removed image memory 1247 may be read by a personal computerprovided separately.

In the electronic endoscope 1200, pick-up image data may be transmittedto an external monitor so that the pick-up image may be observed on linethrough the external monitor. In addition, operation instructions may beinputted from the outside. In this case, without performing imageprocessing, the CPU 1201 transmits the image pick-up signal acquiredfrom the imaging device 1249, to an external video processor in anintact manner. Then, the object image obtained by image processing inthe video processor may be displayed on an external monitor. Thecommunication between the external video processor, the externalmonitor, and the CPU 1201 may be of cable or wireless. In a case thatthe communication is of cable, an external power source becomesemployable when a power source line is included in the wiring.

According to the electronic endoscope 1200 of the present embodimentdescribed above, a stepped part (the open end part 1213 b of thetransparent cover 1213) is formed in a part of the outer shell of theelectronic endoscope 1200. Then, for example, when insertion isperformed until the stepped part is pressed against the wall surface ofthe subject, the tube body is simply and reliably allowed to reach anarrow and small site located at the observation position. This permitseasy insertion of the electronic endoscope tip into a narrow and smallsite, and still permits easy and accurate acquisition of detailed entirecircumferential image information over a large region. In place of theconfiguration that the stepped part is provided in the transparent cover1213, the transparent cover 1213 may be formed in a straight shape andthe stepped part may be provided in the body part 1211. As such, thestepped part may be provided at an arbitrary position in the shapedouter shell. However, the position of the stepped part is preferably setup with taking into consideration the insertion length into thedestination of insertion.

Further, in a case that the stepped part is formed in an annular shapewhose diameter is expanded isotropically relative to the electronicendoscope 1200, the electronic endoscope is constructed compact incomparison with a decentered configuration. Further, in the case of anannular stepped part, even when the electronic endoscope 1200 isinserted into the subject in an arbitrary orientation, anycircumferential position of the stepped part is reliably pressed againstthe wall surface of the subject. Thus, the tube body of the tip of theelectronic endoscope is allowed to reliably reach a desired observationposition.

That is, as shown in FIG. 89, when the inside of a small-diameter hole1297 located on the deep side of a hole 1296 serving as a subject is tobe observed, in a straight-pipe shaped electronic endoscope, it isdifficult for the tip part to reach the small-diameter hole 1297.However, in the electronic endoscope 1200, since the transparent coverserving as an observation window having a smaller diameter is providedat the tip, insertion into the small-diameter hole 1297 is guided sothat the insertion operation becomes easy. Further, starting theinsertion from the state shown in FIGS. 89A and 89B, when the inner wallsurface 1298 of the entrance of the small-diameter hole 1297 abutsagainst the open end part 1213 b of the transparent cover 1213 servingas a stepped part as shown in FIG. 89C, deeper insertion is prevented.As such, the insertion length is restricted by the stepped part. Thus,the electronic endoscope 1200 is reliably located at the targetobservation position by easy operation in comparison with a case thatinsertion operation is performed with paying attention to the detailedinsertion amount. By virtue of this, at the target observation position,detailed entire circumferential image information is acquired simply andaccurately.

Here, in place of the form of a flat surface extending in a directionperpendicular to the direction of insertion of the electronic endoscope1200, the stepped part may be formed in an appropriately arbitraryshape, like a tapered surface whose diameter is reduced toward theinsertion tip side. For example, in place of construction from a singleflat surface, the stepped part may be constructed from a plurality ofsurfaces.

As described above with reference to the electronic endoscope 1200serving as an example, the present specification has disclosed anelectronic endoscope for acquiring an image of the inside of a subject,the electronic endoscope characterized by comprising: a tube body whoseone-end part is closed and whose at least side surface has transparency;a body part that is provided continuously to the-other-end side of thetube body so as to form an outer shell; an introductory optical partthat guides external light acquired through the side of the tube bodywithin the tube body toward the axis direction of the tube body; animage pick-up section that receives the external light introduced fromthe introductory optical part so as to convert the light into anelectric signal; and a driving section that causes the introductoryoptical part to advance or retreat in the axis direction of the tubebody, wherein the one-end side of the tube body is formed in a smallerdiameter than the body part so that a stepped part which is constructedfrom the diameter difference between the tube body and the body part isformed.

According to this electronic endoscope, since the stepped part is formedin a part of the outer shell, for example, when insertion is performeduntil the stepped part is pressed against the wall surface of thesubject, the tube body is simply and reliably allowed to reach a narrowand small site located at the observation position. This permits easypositioning of the electronic endoscope tip to a desired position of anarrow and small site, and still permits easy and accurate acquisitionof detailed entire circumferential image information over a largeregion.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the stepped part is composed of an annular steppedpart whose diameter is expanded isotropic relative to the center axis ofthe tube body.

According to this electronic endoscope, since the annular stepped partwhose diameter is expanded isotropic, even when the electronic endoscopeis inserted into a subject in an arbitrary orientation, anycircumferential position of the stepped part is reliably pressed againstthe wall surface of the subject. Thus, the tube body of the tip of theelectronic endoscope is allowed to reliably reach a desired observationposition. Further, the isotropic diameter expansion realizes a compactshape of the electronic endoscope.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the driving section includes: a female screw whichis formed in the inner peripheral surface of the cylindrical part of thebody part; a revolving body whose one-end part is connected to theintroductory optical part and whose pedestal part is arranged in thecylindrical part, wherein a male screw to be screwed into the femalescrew is formed in the outer peripheral surface of the pedestal part;and a revolution driving section which drives and revolves the revolvingbody about the center axis of the cylindrical part so as to move therevolving body in the center axis direction.

According to this electronic endoscope, light of the sideward regionrelative to the direction of insertion into the subject is acquiredcontinuously in the circumferential direction by a simple configurationcomposed of screwing between the male screw and the female screw.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the revolution driving section includes: anannular gear whose face width direction is in parallel to the centeraxis of the cylindrical part and which is formed in the inner peripheralsurface of the revolving body; a gear wheel which is arranged inside therevolving body and which engages with the annular gear; and a motorwhich drives and revolves the gear wheel.

According to this electronic endoscope, when the motor revolves, thegear wheel revolves. Then, in accordance with this, the revolving bodyrevolves so as to move in the axial direction in the inside of the bodypart. In association with this motion, the introductory optical partlinked to the revolving body revolves and moves in the axial directionin the inside of the tube body.

Further, the present specification has disclosed an electronic endoscopecharacterized in that, in the introductory optical part, an imagepick-up hole is formed in the peripheral surface, an objective lens ismounted in the open end part of the image pick-up hole, and a mirror ismounted that deflects the optical path to the optical axis of theobjective lens.

According to this electronic endoscope, external light acquired from thesideward region of the tube body via the objective lens is deflected tothe tube body axial direction by the mirror in the vicinity of theobjective lens. Thus, the optical path is constructed compact, and hencediameter reduction of the tube body is allowed.

Further, the present specification has disclosed an electronic endoscopecharacterized by comprising: a half mirror that is arranged in themiddle of the optical path between the introductory optical part and theimaging device; and a light emitting body that emits light to beprojected through the introductory optical part after reflection by thehalf mirror and thereby illuminates the subject.

According to this electronic endoscope, the emitted light from the lightemitting body is reflected toward the subject by the half mirror. Then,this reflected light serves as light for illumination that illuminatesthe entire sideward circumference of the subject.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a control section which performs image processingon an image signal obtained by image pick-up performed by the imagepick-up section and an image memory which stores image data obtained byimage processing performed by the control section are included in theinside of the body part.

According to this electronic endoscope, image data obtained by imageprocessing in the control section is stored into the image memory builtin the body part. This permits acquisition of an image by the electronicendoscope in a stand alone mode. Thus, easy handling is enhanced.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a power battery which supplies electric power tothe image pick-up section and the driving section is built inside thebody part.

According to this electronic endoscope, the power battery is built inthe body part. This avoids the necessity of power supply from theoutside, and hence avoids the necessity of a power supply cableconnected from the outside of the body part. Thus, easy handling isenhanced.

The electronic endoscope 1301 shown in FIGS. 90 to 92 includes an outershell composed of the body part 1311 and the transparent cover 1313.Then, its inside is provided with: a lens holder 1319 that holds anobjective lens 1317 for focusing object light through the transparentcover 1313; a driving section 1321 for moving the lens holder 1319 inthe inside of the outer shell; and a solid-state imaging device 1323that receives the object light acquired through the objective lens 1317and then converts the light into an electric signal.

The body part 1311 constituting a part of the outer shell is fabricatedfrom resin material or the like having light shielding property andformed into a cylindrical shape whose one-end part 1311 a is closed andwhose the other end part 1311 c is open. The closed end part (bottompart) 1311 a is provided with a tube-shaped battery accommodating part1311 b. The battery accommodating part 1311 b is closed by a battery lid1327 after a power battery 1325 is mounted.

In the example shown in the figure, in the bottom part 1311 a, two pipes1329 protrude outward from the outer shell. For example, in a case thatimage data and an image map stored in a memory 1383 described later areto be transferred to an external device, data transfer cables areinserted through and protected by the pipes 1329. The pipes 1329 may befabricated from soft material, or alternatively may be fabricated fromhard material so as to serve as a grip used for inserting or extractingthe electronic endoscope 1301 into or from a hole serving as a subjectduring the use of the electronic endoscope 1301.

The transparent cover 1313 formed in a cylindrical shape whose one-endpart 1313 b is open. In the transparent cover 1313, the open end part1313 b is aligned with the open end part 1311 c of the body part 1311,and then fixed to the body part 1311 by appropriate means such asbonding.

The other end part (tip part) 1313 a of the transparent cover 1313 isformed in a smooth hemispherical shape for permitting easy insertioninto a hole serving as a subject. Then, the tip part 1313 a and the openend part 1313 b are connected by a cylindrical part 1313 c having thesame diameter as the tip part 1313 a. In the electronic endoscope 1301,the tip part 1313 a and the cylindrical part 1313 c are formed in asmaller diameter than the open end part 1313 b. As such, since thehemispherically formed tip part 1313 a and the cylindrical part 1313 care formed in a small diameter, easy insertion into a narrow hole isachieved so that the range of application of the electronic endoscope1301 is expanded.

The transparent cover 1313 having the above-mentioned configuration isfabricated from transparent resin material or the like by integralmolding or the like. Alternatively, the hemispherically formed tip part1313 a, the open end part 1313 b, and the cylindrical part 1313 c may befabricated as separate members, and then may be joined to each other byappropriate means as such bonding. In this case, at least thecylindrical part 1313 c serving as a window part facing the innerperipheral surface of a hole serving as a subject is formed transparent.Here, in the present invention, the term “transparent” indicates thatthe material is transparent to light at a particular wavelengthsensitive to the imaging device 1323. That is, the material need not betransparent to visible light.

The lens holder 1319 is formed from resin material or the like and has:a cylindrical to-be-driven section 1333 fit into the body part 1311; anda cylindrical support part 1315 that is formed in a smaller diameterthan the to-be-driven section 1333 and that can enter the cylindricalpart 1313 c of the transparent cover 1313.

In the outer peripheral surface of the to-be-driven section 1333 of thelens holder 1319, a male screw 1333 b is formed that is screwed into thethread groove 1311 d formed in the inner peripheral surface of the bodypart 1311. Further, in the inner peripheral surface of the to-be-drivensection 1333, an internal-tooth gear 1333 a is formed. The gear teeth ofthe internal-tooth gear 1333 a extend in parallel to the center axis ofthe to-be-driven section 1333, and are formed at equal intervals in thecircumferential direction.

Further, in the support part 1315 of the lens holder 1319, its outerdiameter is formed somewhat smaller than the inner diameter of thecylindrical part 1313 c of the transparent cover 1313 so that thesupport part 1315 moves in the inside of the cylindrical part 1313 calong the center axis of the outer shell smoothly without chattering.

In the tip part of the support part 1315, a mirror 1316 is accommodated.The mirror 1316 is formed in an approximately cylindrical shape. Itslower end has a shape having been cut by a plane intersecting the centeraxis at 45 degrees. This inclined cut plane is formed into an objectivereflecting surface 1316 b by formation of a reflection film or the like.

Then, an image pick-up hole is formed at a site in the support part 1315facing in a radial direction the objective reflecting surface 1316 b ofthe mirror 1316. Then, the objective lens 1317 is attached in this imagepick-up hole. Then, object light is focused along the cylindrical part1313 c of the transparent cover 1313 by the objective lens 1317 so as totravel to the mirror 1316 in the form of a parallel light beam. Then,the object light is reflected by the objective reflecting surface 1316 bof the mirror 1316, travels along the center axis of the support part1315 that agrees with the center axis of the outer shell withmaintaining the form of a parallel light beam.

In the inside of the body part 1311, an image pick-up drive unit part1337 is arranged at a position located on an extended line of the centeraxis of the support part 1315 of the lens holder 1319. The image pick-updrive unit part 1337 is fixed inside the body part 1311 by a fixingmember (not shown). In the example shown in the figure, the imagepick-up drive unit part 1337 has three base plates 1341, 1342, and 1343.

The solid-state imaging device 1323 is provided on a base plate 1343arranged most adjacent to the lens holder 1319. The imaging device 1323may be a CCD type imaging device, a CMOS type imaging device, or thelike. A memory 1383 is mounted on a base plate 1342 arranged under thebase plate 1343 (on the bottom part 1311 a side of the body part 1311).The memory 1383 stores image data and the like generated from imagepick-up signals read out from the imaging device 1323. Further, acontrol unit 1345 is mounted on a base plate 1341 arranged under thebase plate 1342. The control unit 1345 performs, for example, read ofimage pick-up signals from the imaging device 1323 and generation ofimage data on the basis of the read-out image pick-up signals.

The imaging device 1323 is arranged on the base plate 1343 at a positionlocated on an extended line of the center axis of the support part 1315of the lens holder 1319. Then, a focusing lens 1351 is arranged at aposition located above the imaging device 1323 and located on anextended line of the center axis of the support part 1315. The focusinglens 1351 is held by a focusing lens holder 1349 provided on the baseplate 1343 in a manner of surrounding the imaging device 1323. Thefocusing lens 1351 causes the object light traveling in the form of aparallel light beam along the center axis of the support part 1315 to befocused on the light acceptance surface of the imaging device 1323 sothat image formation is achieved. As such, the objective lens 1317, theobjective reflecting surface 1316 b of the mirror 1316, and the focusinglens 1351 constitute an objective optical system.

The electronic endoscope 1301 includes a light emitting diode (LED) 1355serving as a light source for emitting light for illuminating theimage-taking object. The LED 1355 is accommodated in the tip part 1313 aof the transparent cover 1313 in such a manner that the LED 1355 isdeparting from the solid-state imaging device 1323 in the axialdirection of the outer shell and that the lens holder 1319 intervenesbetween the LED 1355 and the imaging device 1323. Further, in the insideof the tip part 1313 a, accommodated are: a battery 1356 for supplyingelectric power to the LED 1355; and an illumination lens 1357 forfocusing the light for illumination from the LED 1355. The LED 1355, thebattery 1356, and the illumination lens 1357 are fixed to the tip part1313 a of the transparent cover 1313 by a holding member 1358.

At the tip of the support part 1315 of the lens holder 1319, athrough-hole 1315 a is formed that exposes the upper end part of themirror 1316 accommodated in the tip part. The upper end part of themirror 1316 has a shape having been cut by a plane intersecting thecenter axis. The inclined cut plane is formed into an illuminationreflecting surface 1316 a by formation of a reflection film or the like.The light for illumination from the LED 1355 transmits through theillumination lens 1357, then travels along the extended line of thecenter axis of the support part 1315, and then enters the illuminationreflecting surface 1316 a of the mirror 1316 exposed through thethrough-hole 1315 a.

The illumination reflecting surface 1316 a of the mirror 1316 isinclined approximately symmetrically to the objective reflecting surface1316 b with respect to a virtual surface that is located in betweenrelative to the objective reflecting surface 1316 b and that isperpendicular to the center axis. Then, in the support part 1315 of thelens holder 1319, a projection exit 1315 b is formed at a site that islocated above the objective lens 1317 and that faces the illuminationreflecting surface 1316 a of the mirror 1316 in a radial direction. Thelight for illumination having entered the illumination reflectingsurface 1316 a is reflected by the illumination reflecting surface 1316a toward the projection exit 1315 b, and then projected from theprojection exit 1315 b through the cylindrical part 1313 c of thetransparent cover 1313 onto the image-taking object.

The inclination angle of the illumination reflecting surface 1316 a isset up appropriately such that the optical axis of the light forillumination projected from the projection exit 1315 b is in parallel tothe lens optical axis of the objective lens 1317 or alternativelyapproaches the lens optical axis of the objective lens 1317 when goingoutward from the outer shell. The aperture diameter of the projectionexit 1315 b is also set up appropriately. Thus, the light forillumination projected from the projection exit 1315 b onto theimage-taking object illuminates the region containing the view fieldregion of the objective lens 1317. Here, the projection exit 1315 b ispreferably arranged at a position adjacent to the objective lens 1317 inthe axial direction of the outer shell. By virtue of this, for example,in a case that an image-taking object located extremely close is to betaken, illumination of the region containing the view field region ofthe objective lens 1317 becomes easy.

As such, the illumination lens 1357, the illumination reflecting surface1316 a of the mirror 1316, and the projection exit 1315 b constitute anillumination optical system. Here, the objective reflecting surface 1316b of the objective optical system and the illumination reflectingsurface 1316 a of the illumination optical system are formed in themirror 1316. Thus, the optical member is shared by the objective opticalsystem and the illumination optical system. This reduces the number ofcomponents and hence realizes size reduction.

In the lens holder 1319 in which the male screw 1333 b formed in theouter peripheral surface of the to-be-driven section 1333 is screwedinto the thread groove 1311 d formed in the inner peripheral surface ofthe body part 1311, its movement is guided along the center axis of thebody part 1311, that is, along the center axis of the outer shell. Thedriving section 1321 for moving the lens holder 1319 along the centeraxis of the outer shell is described below in detail.

A stepping motor 1361 is fixed inside the body part 1311. Further, anidle gear wheel 1365 is provided that is located between and engagingwith both of the motor gear wheel 1363 of the stepping motor 1361 andthe internal-tooth gear 1333 a formed in the to-be-driven section 1333of the lens holder 1319. The revolution of the stepping motor 1361 istransmitted through the motor gear wheel 1363 and the idle gear wheel1365 to the lens holder 1319. Here, as the source of power for drivingand revolving the lens holder 1319 is not limited to a stepping motoroperated by pulse drive, and may be a motor of a diverse kind such as aservo motor provided with an encoder, or alternatively may be a powersource of another type.

In the lens holder 1319, the to-be-driven section 1333 is fit into thebody part 1311. Thus, when revolution of the stepping motor 1361 istransmitted, the lens holder 1319 revolves about the center axis of thebody part 1311. At the same time, by using the male screw 1333 b formedin the outer surface, the to-be-driven section 1333 is screwed into thethread groove 1311 d formed in the inner peripheral surface of the bodypart 1311 Thus, in association with revolution about the center axis ofthe body part 1311, the lens holder 1319 moves (is raised or lowered)along the center axis of the body part 1311.

For example, in a situation that the lens holder 1319 is located at araised position shown in FIG. 92, the stepping motor 1361 is revolved ina predetermined direction so that the lens holder 1319 is revolved viathe motor gear wheel 1363 and the idle gear wheel 1365. FIG. 93 shows astate that the lens holder 1319 has gone half around. As shown in FIG.93, the lens holder 1319 revolves about the center axis of the body part1311 so as to be lowered by Δh along the center axis of the body part1311. Then, in accordance with the revolution of the lens holder 1319,the objective lens 1317 is also revolved so that the field of view ofimage pick-up moves in the circumferential direction. The lens holder1319 is allowed, in association with the revolution, to be lowered alongthe center axis of the body part 1311 up to the lowermost position shownin FIG. 94, that is, a position where the lower end of the male screw1333 b of the to-be-driven section 1333 reaches the lower end of thethread groove 1311 d of the body part 1311.

FIG. 95 is a functional block diagram showing the image pick-up driveunit part 1337. In the image pick-up drive unit part 1337, the controlunit 1345 includes: an LED drive circuit 1385 for driving the LED 1355;an imaging device driver 1387 for driving the imaging device 1323; amotor driver 1389 for driving the stepping motor 1361; a pulse generator1391 for providing driving pulses to the motor driver 1389; and acontrol section (CPU) 1381 for controlling the operation of the LEDdrive circuit 1385, the imaging device driver 1387, and the pulsegenerator 1391. Further, the memory 1383 stores a control program forthe control unit 1345. Here, the memory 1383 stores a control program,stores image data, and serves also as a work memory. The control section1381 performs appropriate image processing onto image pick-up signalsread from the imaging device 1323, so as to generate image data, andthen stores the generated image data into the memory 1383. Thisconfiguration allows the electronic endoscope 1301 in a stand alone modeto acquire and save images of image-taking objects. This providesexcellence in easy handling.

When the power switch 1393 of the electronic endoscope 301 is closed,electric power from the power battery 1325 and the battery 1356 issupplied to the individual parts of the electronic endoscope 1301through wiring (not shown) so that image pick-up is performed. Forexample, the power switch 1393 may be provided in the bottom part 1311 aof the body part 1311, and may be opened or closed by manual operation.Alternatively, a switch terminal that follows magnetism may be built inthe body part 1311. Then, from the outside of the electronic endoscope1301, a magnet may be brought close or apart so that the switch terminalmay be opened or closed.

Next, the operation of the electronic endoscope 1301 is described below.When the power switch 1393 is turned ON, electric power is supplied fromthe power battery 1325 and the battery 1356 to the individual parts ofthe electronic endoscope 1301. Then, the light for illumination from theLED 1355 is projected from the projection exit 1315 b through thecylindrical part 1313 c of the transparent cover 1313 toward thesideward region so that the image-taking object is illuminated.Reflected light from the image-taking object is acquired into theelectronic endoscope 1301 through the cylindrical part 1313 c and theobjective lens 1317 of the transparent cover 1313, so that an image isformed onto the light acceptance surface of the imaging device 1323 bythe focusing lens 1351. Then, charge accumulated in the imaging device1323 as a result of photoelectric conversion is read as an image pick-upsignal by the control section 1381 of the control unit 1345. The controlsection 1381 performs appropriate image processing onto the read-outimage pick-up signal so as to generate image data, and then stores thegenerated image data into the memory 1383.

FIG. 96 is a flow chart showing the processing procedure of a controlprogram of the control unit 1345. When the power switch 1393 is turnedON, first, the stepping motor 1361 is driven and revolved, so that thelens holder 1319 goes along the center axis of the outer shell of theelectronic endoscope 1301 to a home position (step S1). Here, in thefollowing description, the home position is defined as a position where,for example, as shown in FIG. 92, the objective lens 1317 is located onthe tip side of the electronic endoscope 1301. However, the definitionis not limited to this, and may be the opposite position where theobjective lens 1317 is located on the pedestal side (the position shownin FIG. 94).

After the lens holder 1319 is set at the home position, image pick-upprocessing is performed (step S2). The image pick-up processing includessuch processes that the LEE) 1355 is driven so as to emit light forillumination; object light is acquired through the objective lens 1317into the electronic endoscope 1301 so that an image is formed onto thelight acceptance surface of the imaging device 1323; and on the basis ofthe image pick-up signal read from the imaging device 1323, image datais generated and then stored into the memory 1383.

Then, the stepping motor 1361 is driven by a specified number of pulses(step S3), so that the lens holder 1319 is lowered by a predetermineddistance. Until the lens holder 1319 reaches the most lowered position(step S4), image pick-up processing is performed at each destination ofthe movement (step S2). When the lens holder 1319 reaches the mostlowered position, the lowering operation of the lens holder 1319 and theimage pick-up processing are terminated (step S4).

FIG. 97 is a diagram illustrating the movement of the field of view ofimage pick-up achieved when the above-mentioned steps S2 to S4 areexecuted repeatedly. In the first occasion of image pick-up processingperformed at the home position, image pick-up is performed in the fieldof view “No.001”, and hence image data of the field of view “No.001” isgenerated from the image pick-up signal read from the imaging device1323.

Once the image pick-up processing in the field of view “No.001” iscompleted, the stepping motor 1361 is driven at step S3 by a specifiednumber of pulses so that the lens holder 1319 is lowered and revolved.In association with this, the objective lens 1317 held by the lensholder 1319 is moved so that the field of view moves to “No.002” in FIG.97. At that time, the projection exit 1315 b provided in the lens holder1319 is moved similarly to the objective lens 1317 and thereby followsthe moving field of view so as to illuminate the field of view “No.002”.Then, image pick-up is performed in this field of view, and hence imagedata of the field of view “No.002” is generated from the image pick-upsignal read from the imaging device 1323.

Here, the lens holder 1319 is located in between the LED 1355 and thesolid-state imaging device 1323 separated in the axial direction of theouter shell, and is moved along the axis of the outer shell. Thus, theoptical path length from the LED 1355 to the solid-state imaging device1323 is approximately fixed regardless of the movement of the lensholder 1319. For example, when the lens holder 1319 is located at thehome position shown in FIG. 92, the objective optical system (theobjective lens 1317→the objective reflecting surface 1316 b of themirror 1316→the focusing lens 1351→the solid-state imaging device 1323)has a longer optical path length than the illumination optical system(the illumination reflecting surface 1316 a→the projection exit 1315 bof the LED 1355→the illumination lens 1357→the mirror 1316). Incontrast, when the lens holder 1319 is located at the lowermost positionshown in FIG. 94, the optical path length of the illumination opticalsystem is extended, and the optical path length of the objective opticalsystem is reduced by the same amount. Thus, the optical path length L5from the LED 1355 to the solid-state imaging device 1323 in a situationthat the lens holder 1319 is located at the home position is almostequal to the optical path length L6 from the LED 1355 to the solid-stateimaging device 1323 in a situation of the lowermost position. As aresult, the intensity of light attenuation by scattering and the likeoccurring in the course from the LED 1355 to the solid-state imagingdevice 1323 becomes almost the same for these two optical paths. Thus,the intensity of light entering the solid-state imaging device 1323 isfixed approximately.

After that, image pick-up processing is repeated with moving the fieldof view like “No.003”→“No.004”→“No.005” . . . . When the lens holder1319 has gone one around from the home position, the field of view ofimage pick-up is located at “No.011” in FIG. 97. In case of having gonearound twice, the field of view of image pick-up is located at “No.021”in FIG. 97. In the present embodiment, plural pieces of image datastored in the memory 1383 are arranged similarly to the exemplarymovement of the field of view shown in FIG. 97 so that an image map isgenerated (step S5).

Here, for example, the number of pulses provided to the stepping motor1361 at step S3 may be adjusted appropriately, or alternatively thescrew pitch of the thread groove 1311 d of the body part 1311 and themale screw 1333 b of the to-be-driven section 1333 may be adjustedappropriately, so that circumferentially adjacent fields of view ofimage pick-up may be positioned such that their left and right edgeparts should be in contact with each other or overlapping somewhat witheach other, and so that axially adjacent fields of view of image pick-upmay be positioned such that their upper and lower edge parts should bein contact with each other or overlapping somewhat with each other.According to this configuration, image taking of an object is achievedwithout a missing part in the axial and the circumferential directions.Thus, an image map without a gap is obtained.

When the above-mentioned image map has been generated, the image map isto be read from the memory 1383 to the outside. This read may beperformed by wireless, or alternatively through a cable in aconfiguration that a data transfer cable is inserted through the pipe1329 shown in FIG. 90 and connected to the image pick-up drive unit part1337. Alternatively, the memory 1383 may be provided in a removablemanner from the electronic endoscope 1301. Then, the removed memory 1383may be read by a personal computer provided separately.

As described above with reference to the electronic endoscope 1301serving as an example, the present specification has disclosed anelectronic endoscope characterized by comprising: an outer shell that isformed in a tube shape and whose peripheral wall is provided with atransparent window part extending in an axial direction; a light sourceand a solid-state imaging device that are provided inside the outershell; an illumination optical system that projects light forillumination from the light source through the window part onto animage-taking object; an objective optical system that includes anobjective lens which focuses object light through the window part andthat forms an image onto the solid-state imaging device; a lens holderthat holds at least the objective lens in the objective optical system;and a driving section that moves the lens holder along the axis of theouter shell, wherein the light source is arranged departing from thesolid-state imaging device in the axial direction of the outer shell,wherein the lens holder is moved between the light source and thesolid-state imaging device along the axis of the outer shell, andwherein the projection exit of the illumination optical system isprovided in the lens holder.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the projection exit of the illumination opticalsystem is arranged at a position adjacent to the objective lens in theaxial direction of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that: the illumination optical system includes a firstreflecting surface which reflects the light for illumination toward theprojection exit; the objective optical system includes a secondreflecting surface which reflects the object light toward thesolid-state imaging device; the light source and the solid-state imagingdevice are arranged on the same axis; and the first reflecting surfaceand the second reflecting surface are formed in a single optical memberarranged on the axis.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the window part is provided over the entirecircumference of the peripheral wall of the outer shell, and wherein thedriving section causes the lens holder to revolve about the axis of theouter shell and thereby move along the axis of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the outer shell is formed in a cylindrical shapeand the inner peripheral surface of its inner wall is provided with athread groove, wherein the driving section includes a motor which drivesand revolves the lens holder about the axis of the outer shell, andwherein the lens holder engages with the thread groove of the outershell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that a control section which reads an image pick-upsignal from the solid-state imaging device and then generates image dataand a memory which stores the image data are further included in theinside of the outer shell.

Further, the present specification has disclosed an electronic endoscopecharacterized in that the driving section is driven by electric power,and wherein a power battery which supplies electric power to the lightsource, the solid-state imaging device, and the driving section isfurther provided inside the outer shell.

Next, preferred examples of use of the electronic endoscopes describedabove are given below.

(i) Example of Use as Hysteroscope

In recent years, the lowering trend in the age of women suffering fromcervical cancer is growing. In case that cervical cancer is found atearly stages, serious results are avoided by partial extirpation. Thus,early detection is important. Nevertheless, women hesitate to exposetheir own bodies, and hence the population who receive medical checkupis not growing.

Each electronic endoscope described above is effective in medicalcheckup for cervical cancer, when the dimensions and the shape aredesigned appropriately. When the electronic endoscope is inserted intothe vaginal cavity of a woman and then the electronic endoscope isinserted from the apex part into the uterine cervix such that a seriesof the field of view of image pick-up positions should reach the uterinecervix, image pick-up is achieved for the situation of the innerperipheral surface of the uterine cervix without a missing part.

As a mode of use, for example, the electronic endoscope may be insertedinto the uterine cervix by the patient herself in the consultation room.Further, the doctor staying in another room may instruct the insertionposition and check the pick-up image through a monitor on line. Thiseases the patient's mental burden, and hence contributes to an increasein the population who receive medical checkup.

In particular, at the time when the electronic endoscope 1200 describedabove is inserted from the inside of the vaginal cavity further into thecanal of the cervix, the inner wall of the vaginal portion of the cervixat the entrance of the canal of the cervix abuts against the steppedpart of the electronic endoscope 1200 so that the amount of insertion ofthe electronic endoscope 1200 is restricted. Thus, the tip of theelectronic endoscope 1200 is reliably positioned at the inner wallsurface of the canal of the cervix. Further, also from the perspectiveof the insertion length, the insertion is stopped at an appropriateposition.

Further, in each electronic endoscope described above, when the powerswitch is turned ON, the objective lens returns to the home positionautomatically and then image pick-up processing is performedautomatically. Thus, the electronic endoscope may be lent to thepatient, and then the patient herself may acquire an image of her ownuterine cervix in her home. Then, the doctor receives the electronicendoscope and then checks the pick-up image data in the memory so thatdiagnosis is performed.

(ii) Example of Use as Electronic Endoscope for Large Intestine andRectum

When medical checkup is performed for the large intestine or the rectum,in the prior art, observation has been performed by using an electronicendoscope in which an imaging device is mounted on the tip part. Thus,the diseased part has been observed obliquely from the above. Incontrast, when any one of the electronic endoscopes described above isinserted to the diseased part position and then observation isperformed, the diseased part is observed perpendicularly from the above.This permits more detailed observation and accurate diagnosis.

(iii) Example of Use as Industrial Endoscope

Each electronic endoscope described above may be used as an industrialendoscope, for example, used for observing a fine crack in a thinpiping. At the time, an electronic endoscope is prepared that hasdimensions and a shape in accordance with the size of the opening of ahole or a gap serving as an observation object as well as with theinsertion depth. As described above, observation of the crack or thelike is performed from the above perpendicularly to the inner peripheralsurface of the hole, and hence more detailed observation is achieved.Further, once the electronic endoscope is inserted, observation isallowed for a large region. This reduces the rate of overlooking smallcracks.

INDUSTRIAL APPLICABILITY

According to the present invention, detailed image information over alarge region is acquired easily and accurately.

The present invention has been described above in detail with referenceto particular embodiments. However, it is clear for the person skilledin the art that various modifications and variations can be made withoutdeparting from the spirit and the scope of the present invention. Thepresent application is based on Japanese Laid-Open Patent ApplicationNos. 2008-157991, 2008-157992, 2008-157993, 2008-157999, 2008-158000,2008-158002, 2008-158004, 2008-158005, 2008-158006, and 2008-158013filed on Jun. 17, 2008. Their contents are incorporated herein byreference.

REFERENCE SIGNS LIST

-   -   1 endoscope    -   11 body part (outer shell)    -   13 transparent cover (outer shell)    -   13 c cylindrical part (window part)    -   16 objective mirror (objective optical system)    -   17 objective lens (objective optical system)    -   19 lens holder    -   21 driving section    -   23 solid-state imaging device    -   25 power battery    -   51 focusing lens (objective optical system)    -   61 stepping motor    -   67 feed screw    -   81 control section    -   83 memory    -   500 electronic endoscope    -   511 body part    -   511 a bottom part    -   511 b battery accommodating part    -   511 c open end part    -   513 transparent cover section    -   513 a hemispherical part    -   513 b open end part    -   513 c cylindrical part    -   513 d shaft hole    -   515 tube-shaped part    -   517 objective lens group    -   517A wide-angle lens    -   517B lens    -   519 lens holder    -   521 raising and lowering driving section    -   523 imaging device    -   525 power battery    -   527 battery lid    -   529 wiring protection tube    -   531 rib    -   533 flange    -   535 engagement groove    -   537 image pick-up drive unit part    -   541, 542, 543 base plate    -   545 control unit    -   547 image memory    -   549 focusing lens holder    -   551 focusing lens    -   553 half mirror    -   555 light emitting diode    -   557 illumination lens    -   561 stepping motor    -   563 motor gear wheel    -   565 idle gear wheel    -   567 feed screw    -   569 gear wheel    -   571 support arm    -   573 opening    -   575 feed nut    -   577 nut holding piece    -   581 control section    -   583 memory    -   585 LED drive circuit    -   587 imaging device driver    -   591 pulse generator    -   593 power switch    -   W view field region    -   601 electronic endoscope    -   602 body part    -   602 a bottom part    -   602 b battery accommodating part    -   602 c female screw provided in the inner peripheral surface    -   603 transparent capsule (transparent cover)    -   603 a hemispherical part at tip    -   603 c cylindrical part    -   604 moving lens frame section (lens holder)    -   604 a disk-shaped objective lens mount part    -   604 b cylindrical member    -   604 c male screw provided in outer peripheral surface    -   604 d internal-tooth gear    -   604 f image pick-up hole    -   605 image pick-up drive unit part    -   611 power battery    -   612 battery lid    -   613, 614 grip pipe    -   616 objective mirror    -   617 objective lens    -   621, 622, 623 base plate    -   626 image memory    -   627 solid-state imaging device    -   628 stepping motor    -   629 lens holder    -   630 focusing lens    -   631 half mirror    -   632 illumination lens    -   633 LED (light emitting body)    -   636 motor gear wheel    -   637 idle gear wheel    -   641 control device (CPU)    -   647 power switch

What is claimed is:
 1. An electronic endoscope comprises: an outer shellthat is formed in a tube shape and whose peripheral wall is providedwith a transparent window part extending in an axial direction; asolid-state imaging device that is provided inside the outer shell; anobjective optical system that includes an objective lens for focusingobject light through the window part and that forms an image onto thesolid-state imaging device; and a drive mechanism that causes at leastthe objective lens in the objective optical system to move along an axisof the outer shell, wherein the drive mechanism includes a lens holderfor supporting the objective lens, a feed screw extending along the axisof the outer shell, and a motor for driving and revolving the lensholder about the feed screw as an axis of revolution, and wherein thelens holder engages with a thread groove of the feed screw.
 2. Theelectronic endoscope according to claim 1, comprising: a control sectionthat reads an image pick-up signal from the solid-state imaging deviceand that generates image data, and a memory that stores the image dataare further included in the outer shell.
 3. The electronic endoscopeaccording to claim 1, wherein the drive mechanism is driven by electricpower, and wherein a power battery for supplying electric power to thesolid-state imaging device and the drive mechanism is further includedin the outer shell.